Fix non-contiguous program indices

* chore: update type testing setup
* stricter TSConfig
* deduplicate type checking

.editorconfig

@@ -0,0 +1,11 @@
+root = true
+
+[*.js]
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.yml]
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true

.git-blame-ignore-revs

@@ -0,0 +1,6 @@
+# Upgrade to Prettier 2.7
+3d228334530860a6e3f99dc10777c84bf22292c1
+# Format markdown files with Prettier
+dfe2eaaf20f0b679d94e5a799757c4394d80f1cc
+# migrate to oxlint and oxfmt
+0c1d00282ca619c3416ad819bdf53c0852b32415

.gitattributes

@@ -0,0 +1,6 @@
+# Handlebars-template fixtures in test cases need deterministic eol
+*.handlebars text eol=lf
+*.hbs text eol=lf
+
+# Lexer files as well
+*.l text eol=lf

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,9 @@
+Before filing issues, please check the following points first:
+
+- [ ] Please don't open issues for security issues. Instead, file a report at https://www.npmjs.com/advisories/report?package=handlebars
+- [ ] Have a look at https://github.com/handlebars-lang/handlebars.js/blob/master/CONTRIBUTING.md
+- [ ] Read the FAQ at https://github.com/handlebars-lang/handlebars.js/blob/master/FAQ.md
+- [ ] Use the jsfiddle-template at https://jsfiddle.net/4nbwjaqz/4/ to reproduce problems or bugs
+
+This will probably help you to get a solution faster.
+For bugs, it would be great to have a PR with a failing test-case.

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,12 @@
+Before creating a pull-request, please check https://github.com/handlebars-lang/handlebars.js/blob/master/CONTRIBUTING.md first.
+
+Generally we like to see pull requests that
+
+- [ ] Please don't start pull requests for security issues. Instead, file a report at https://www.npmjs.com/advisories/report?package=handlebars
+- [ ] Maintain the existing code style
+- [ ] Are focused on a single change (i.e. avoid large refactoring or style adjustments in untouched code if not the primary goal of the pull request)
+- [ ] Have good commit messages
+- [ ] Have tests
+- [ ] Have the [typings](https://www.typescriptlang.org/docs/handbook/declaration-files/introduction.html) (types/index.d.ts) updated on every API change. If you need help, updating those, please mention that in the PR description.
+- [ ] Don't significantly decrease the current code coverage (see coverage/lcov-report/index.html)
+- [ ] Please target the `master` branch in the PR.

.github/dependabot.yml

@@ -0,0 +1,9 @@
+version: 2
+updates:
+  - package-ecosystem: npm
+    directory: '/'
+    open-pull-requests-limit: 0
+    schedule:
+      interval: weekly
+    allow:
+      - dependency-type: production

.github/workflows/ci.yml

@@ -0,0 +1,91 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - master
+  pull_request: {}
+
+jobs:
+  lint:
+    name: Lint
+    runs-on: 'ubuntu-latest'
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: '24'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Lint
+        run: npm run lint
+
+  test:
+    name: Test (Node)
+    runs-on: ${{ matrix.operating-system }}
+    strategy:
+      fail-fast: false
+      matrix:
+        operating-system: ['ubuntu-latest', 'windows-latest']
+        # https://nodejs.org/en/about/releases/
+        node-version: ['20', '22', '24']
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+        with:
+          submodules: true
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: ${{ matrix.node-version }}
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Test
+        run: npm run test
+
+      - name: Test (Publish)
+        if: matrix.node-version != '20'
+        run: npx vitest run --project publish
+
+      - name: Test (Integration)
+        if: matrix.operating-system == 'ubuntu-latest'
+        run: npm run test:integration
+
+  browser:
+    name: Test (Browser)
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+        with:
+          submodules: true
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: '24'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Install Playwright
+        run: |
+          npx playwright install-deps
+          npx playwright install
+
+      - name: Build
+        run: npm run build
+
+      - name: Test
+        run: |
+          npm run test:browser-smoke
+          npm run test:browser

.github/workflows/release.yml

@@ -0,0 +1,39 @@
+name: Release
+
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - master
+    tags:
+      - '*'
+
+jobs:
+  publish-aws-s3:
+    name: Publish to AWS S3
+    runs-on: 'ubuntu-latest'
+    environment: 'builds.handlebarsjs.com.s3.amazonaws.com'
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+        with:
+          submodules: true
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: '24'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Publish
+        run: |
+          git config --global user.email "release@handlebarsjs.com"
+          git config --global user.name "handlebars-lang"
+          npm run publish:aws
+        env:
+          S3_BUCKET_NAME: 'builds.handlebarsjs.com'
+          S3_REGION: 'us-east-1'
+          S3_ACCESS_KEY_ID: ${{ secrets.S3_ACCESS_KEY_ID }}
+          S3_SECRET_ACCESS_KEY: ${{ secrets.S3_SECRET_ACCESS_KEY }}

.gitignore

@@ -1,8 +1,19 @@
-vendor
 .rvmrc
 .DS_Store
-lib/handlebars/compiler/parser.js
-node_modules
+/tmp/
 *.sublime-project
 *.sublime-workspace
 npm-debug.log
+.idea
+/yarn-error.log
+/yarn.lock
+node_modules
+/handlebars-release.tgz
+.nyc_output
+
+# Generated files
+/coverage/
+/dist/
+/tests/bench/results/
+/tests/integration/*/dist/
+/spec/tmp/*

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "spec/mustache"]
+	path = spec/mustache
+	url = https://github.com/mustache/spec.git

.jshintrc

@@ -1,52 +0,0 @@
-{
-    "predef": [
-        "console",
-        "Ember",
-        "DS",
-        "Handlebars",
-        "Metamorph",
-        "ember_assert",
-        "ember_warn",
-        "ember_deprecate",
-        "ember_deprecateFunc",
-        "require",
-        "suite",
-        "equal",
-        "equals",
-        "test",
-        "testBoth",
-        "raises",
-        "deepEqual",
-        "start",
-        "stop",
-        "ok",
-        "strictEqual",
-        "module"
-    ],
-
-    "node" : true,
-    "es5" : true,
-    "browser" : true,
-
-    "boss" : true,
-    "curly": false,
-    "debug": false,
-    "devel": false,
-    "eqeqeq": true,
-    "evil": true,
-    "forin": false,
-    "immed": false,
-    "laxbreak": false,
-    "newcap": true,
-    "noarg": true,
-    "noempty": false,
-    "nonew": false,
-    "nomen": false,
-    "onevar": false,
-    "plusplus": false,
-    "regexp": false,
-    "undef": true,
-    "sub": true,
-    "strict": false,
-    "white": false
-}

.npmignore

@@ -1,10 +0,0 @@
-.DS_Store
-.gitignore
-.rvmrc
-Gemfile
-Gemfile.lock
-Rakefile
-bench/*
-spec/*
-src/*
-vendor/*

.oxfmtrc.json

@@ -0,0 +1,28 @@
+{
+  "$schema": "https://raw.githubusercontent.com/nicolo-ribaudo/oxfmt-config-schema/refs/heads/main/schema.json",
+  "singleQuote": true,
+  "tabWidth": 2,
+  "semi": true,
+  "trailingComma": "es5",
+  "printWidth": 80,
+  "ignorePatterns": [
+    ".rvmrc",
+    ".DS_Store",
+    "/tmp/",
+    "*.sublime-project",
+    "*.sublime-workspace",
+    "npm-debug.log",
+    "sauce_connect.log*",
+    ".idea",
+    "yarn-error.log",
+    "/coverage/",
+    ".nyc_output/",
+    "/dist/",
+    "/tests/integration/*/dist/",
+    "/spec/expected/",
+    "/spec/mustache",
+    "/spec/vendor",
+    "*.handlebars",
+    "*.hbs"
+  ]
+}

.oxlintrc.json

@@ -0,0 +1,150 @@
+{
+  "$schema": "https://raw.githubusercontent.com/oxc-project/oxc/main/npm/oxlint/configuration_schema.json",
+  "plugins": ["eslint", "typescript", "unicorn", "oxc", "node", "vitest"],
+  "categories": {
+    "correctness": "error"
+  },
+  "rules": {
+    "no-console": "warn",
+    "no-func-assign": "off",
+    "no-sparse-arrays": "off",
+
+    "default-case": "warn",
+    "guard-for-in": "warn",
+    "no-alert": "error",
+    "no-caller": "error",
+    "no-div-regex": "warn",
+    "no-eval": "error",
+    "no-extend-native": "error",
+    "no-extra-bind": "error",
+    "no-implied-eval": "error",
+    "no-iterator": "error",
+    "no-labels": "error",
+    "no-lone-blocks": "error",
+    "no-loop-func": "error",
+    "no-multi-str": "warn",
+    "no-global-assign": "error",
+    "no-new": "error",
+    "no-new-func": "error",
+    "no-new-wrappers": "error",
+    "no-proto": "error",
+    "no-return-assign": "error",
+    "no-script-url": "error",
+    "no-self-compare": "error",
+    "no-sequences": "error",
+    "no-throw-literal": "error",
+    "no-unused-expressions": "error",
+    "no-warning-comments": "warn",
+    "no-with": "error",
+    "radix": "error",
+
+    "no-label-var": "error",
+    "no-use-before-define": ["error", { "functions": false }],
+
+    "no-var": "error",
+
+    "node/no-process-env": "error"
+  },
+  "ignorePatterns": [
+    "tmp/",
+    "dist/",
+    "coverage/",
+    ".nyc_output/",
+    "handlebars-release.tgz",
+    "tests/integration/*/dist/",
+    "spec/expected/",
+    "spec/mustache",
+    "spec/vendor",
+    "node_modules",
+    "types/"
+  ],
+  "overrides": [
+    {
+      "files": ["lib/**/*.js"],
+      "env": {
+        "node": false,
+        "browser": true
+      }
+    },
+    {
+      "files": ["spec/**/*.js"],
+      "globals": {
+        "CompilerContext": "readonly",
+        "Handlebars": "writable",
+        "handlebarsEnv": "readonly",
+        "expectTemplate": "readonly",
+        "suite": "readonly",
+        "test": "readonly",
+        "testBoth": "readonly",
+        "raises": "readonly",
+        "deepEqual": "readonly",
+        "start": "readonly",
+        "stop": "readonly",
+        "ok": "readonly",
+        "vi": "readonly",
+        "strictEqual": "readonly",
+        "define": "readonly",
+        "expect": "readonly",
+        "beforeEach": "readonly",
+        "afterEach": "readonly",
+        "describe": "readonly",
+        "it": "readonly"
+      },
+      "rules": {
+        "no-var": "off",
+        "dot-notation": "off",
+        "vitest/no-conditional-tests": "off"
+      }
+    },
+    {
+      "files": ["tasks/**/*.js"],
+      "rules": {
+        "node/no-process-env": "off",
+        "prefer-const": "warn",
+        "dot-notation": "error"
+      }
+    },
+    {
+      "files": ["tasks/tests/**/*.js"],
+      "globals": {
+        "describe": "readonly",
+        "it": "readonly",
+        "expect": "readonly",
+        "beforeEach": "readonly",
+        "afterEach": "readonly",
+        "vi": "readonly"
+      }
+    },
+    {
+      "files": ["tests/bench/**/*.mjs"],
+      "rules": {
+        "no-console": "off"
+      }
+    },
+    {
+      "files": ["tests/integration/multi-nodejs-test/**/*.js"],
+      "rules": {
+        "no-console": "off",
+        "no-var": "off"
+      }
+    },
+    {
+      "files": ["tests/browser/**/*.js"],
+      "env": {
+        "browser": true
+      }
+    },
+    {
+      "files": [
+        "tests/integration/webpack-babel-test/src/**/*.js",
+        "tests/integration/webpack-test/src/**/*.js"
+      ],
+      "env": {
+        "browser": true
+      },
+      "rules": {
+        "no-var": "off"
+      }
+    }
+  ]
+}

.rspec

@@ -1 +0,0 @@
--cfs

.swcrc

@@ -0,0 +1,8 @@
+{
+  "$schema": "https://swc.rs/schema.json",
+  "module": {
+    "type": "commonjs",
+    "importInterop": "swc"
+  },
+  "sourceMaps": "inline"
+}

CONTRIBUTING.md

@@ -0,0 +1,123 @@
+# How to Contribute
+
+## Reporting Security Issues
+
+Please refer to our [Security Policy](https://github.com/handlebars-lang/handlebars.js/blob/master/SECURITY.md).
+
+## Reporting Issues
+
+Please refer to our [FAQ](https://github.com/handlebars-lang/handlebars.js/blob/master/FAQ.md) for common issues that people run into.
+
+Should you run into other issues with the project, please don't hesitate to let us know by filing an [issue][issue]!
+
+In general, we are going to ask for an **example** of the problem failing, which can be as simple as a jsfiddle/jsbin/etc. We've put together a jsfiddle **[template][jsfiddle]** to ease this. (We will keep this link up to date as new releases occur, so feel free to check back here).
+
+Pull requests containing only failing tests demonstrating the issue are welcomed and this also helps ensure that your issue won't regress in the future once it's fixed.
+
+Documentation issues on the [handlebarsjs.com](https://handlebarsjs.com) site should be reported on [handlebars-lang/docs](https://github.com/handlebars-lang/docs).
+
+## Branches
+
+- The branch `master` contains the current development version (v5).
+- The branch `4.x` contains the previous stable version. Only critical bugfixes are backported there.
+
+## Pull Requests
+
+We also accept [pull requests][pull-request]!
+
+Generally we like to see pull requests that
+
+- Maintain the existing code style
+- Are focused on a single change (i.e. avoid large refactoring or style adjustments in untouched code if not the primary goal of the pull request)
+- Have [good commit messages](http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html)
+- Have tests
+- Don't significantly decrease the current code coverage (see coverage/lcov-report/index.html)
+
+## Building
+
+To build Handlebars.js you'll need Node.js installed.
+
+Before building, you need to make sure that the Git submodule `spec/mustache` is included (i.e. the directory `spec/mustache` should not be empty). To include it, if using Git version 1.6.5 or newer, use `git clone --recursive` rather than `git clone`. Or, if you already cloned without `--recursive`, use `git submodule update --init`.
+
+Project dependencies may be installed via `npm install`.
+
+To build Handlebars.js from scratch, run `npm run build` in the root of the project. That will compile CJS modules via SWC and bundle UMD distributions via rspack, outputting results to the dist/ folder. To run tests, use `npm test`.
+
+If you notice any problems, please report them to the GitHub issue tracker at
+[http://github.com/handlebars-lang/handlebars.js/issues](http://github.com/handlebars-lang/handlebars.js/issues).
+
+## Running Tests
+
+To run tests locally, first install all dependencies.
+
+```sh
+npm install
+```
+
+Clone the mustache specs into the spec/mustache folder.
+
+```sh
+cd spec
+rm -r mustache
+git clone https://github.com/mustache/spec.git mustache
+```
+
+From the root directory, run the tests.
+
+```sh
+npm test
+```
+
+## Linting and Formatting
+
+Handlebars uses `oxlint` for linting, `oxfmt` for formatting, and `eslint` (with `eslint-plugin-compat`) for browser API compatibility checks.
+Committed files are linted and formatted in a pre-commit hook.
+
+You can use the following scripts to make sure that the CI job does not fail:
+
+- **npm run lint** will run all linters and fail on warnings
+- **npm run format** will format all files
+- **npm run check-before-pull-request** will perform all checks that our CI job does, excluding integration tests.
+- **npm run test:integration** will run integration tests (bundler compatibility with webpack, rollup, etc.)
+  These tests only work on Linux.
+
+## Releasing the latest version
+
+Before attempting the release Handlebars, please make sure that you have the following authorizations:
+
+- Push-access to `handlebars-lang/handlebars.js`
+- Publishing rights on npmjs.com for the `handlebars` package
+- Publishing rights on gemfury for the `handlebars-source` package
+- Push-access to the repo for legacy package managers: `components/handlebars`
+- Push-access to the production-repo of the handlebars site: `handlebars-lang/handlebarsjs.com-github-pages`
+
+_When releasing a previous version of Handlebars, please look into the CONTRIBUNG.md in the corresponding branch._
+
+A full release may be completed with the following:
+
+```
+npm ci
+npm run build
+npm publish
+```
+
+After the release, you should check that all places have really been updated. Especially verify that the `latest`-tags
+in those places still point to the latest version
+
+- [The npm-package](https://www.npmjs.com/package/handlebars) (check latest-tag)
+- [The bower package](https://github.com/components/handlebars.js) (check the package.json)
+- [The AWS S3 Bucket](https://s3.amazonaws.com/builds.handlebarsjs.com) (check latest-tag)
+- [RubyGems](https://rubygems.org/gems/handlebars-source)
+
+When everything is OK, the **handlebars site** needs to be updated.
+
+Go to the master branch of the repo [handlebars-lang/docs](https://github.com/handlebars-lang/docs/tree/master)
+and make a minimal change to the README. This will invoke a github-action that redeploys
+the site, fetching the latest version-number from the npm-registry.
+(note that the default-branch of this repo is not the master and regular changes are done
+in the `handlebars-lang/docs`-repo).
+
+[generator-release]: https://github.com/walmartlabs/generator-release
+[pull-request]: https://github.com/handlebars-lang/handlebars.js/pull/new/master
+[issue]: https://github.com/handlebars-lang/handlebars.js/issues/new
+[jsfiddle]: https://jsfiddle.net/4nbwjaqz/4/

FAQ.md

@@ -0,0 +1,54 @@
+# Frequently Asked Questions
+
+## How can I file a bug report:
+
+See our guidelines on [reporting issues](https://github.com/handlebars-lang/handlebars.js/blob/master/CONTRIBUTING.md#reporting-issues).
+
+## Why isn't my Mustache template working?
+
+Handlebars deviates from Mustache slightly on a few behaviors. These variations are documented in our [readme](https://github.com/handlebars-lang/handlebars.js#differences-between-handlebarsjs-and-mustache).
+
+## Why is it slower when compiling?
+
+The Handlebars compiler must parse the template and construct a JavaScript program which can then be run. Under some environments such as older mobile devices this can have a performance impact which can be avoided by precompiling. Generally it's recommended that precompilation and the runtime library be used on all clients.
+
+## Why doesn't this work with Content Security Policy restrictions?
+
+When not using the precompiler, Handlebars generates a dynamic function for each template which can cause issues with pages that have enabled Content Policy. It's recommended that templates are precompiled or the `unsafe-eval` policy is enabled for sites that must generate dynamic templates at runtime.
+
+## How can I include script tags in my template?
+
+If loading the template via an inlined `<script type="text/x-handlebars">` tag then you may need to break up the script tag with an empty comment to avoid browser parser errors:
+
+```html
+<script type="text/x-handlebars">
+  foo
+  <scr{{!}}ipt src="bar"></scr{{!}}ipt>
+</script>
+```
+
+It's generally recommended that templates are served through external, precompiled, files, which do not suffer from this issue.
+
+## Why are my precompiled scripts throwing exceptions?
+
+When using the precompiler, it's important that a supporting version of the Handlebars runtime be loaded on the target page. In version 1.x there were rudimentary checks to compare the version but these did not always work. This is fixed under 2.x but the version checking does not work between these two versions. If you see unexpected errors such as `undefined is not a function` or similar, please verify that the same version is being used for both the precompiler and the client. This can be checked via:
+
+```sh
+handlebars --version
+```
+
+If using the integrated precompiler and
+
+```javascript
+console.log(Handlebars.VERSION);
+```
+
+On the client side.
+
+We include the built client libraries in the npm package for those who want to be certain that they are using the same client libraries as the compiler.
+
+Should these match, please file an issue with us, per our [issue filing guidelines](https://github.com/handlebars-lang/handlebars.js/blob/master/CONTRIBUTING.md#reporting-issues).
+
+## How do I load the runtime library when using AMD?
+
+The `handlebars.runtime.js` file includes a UMD build, which exposes the library as both the module root and the `default` field for compatibility.

Gemfile

@@ -1,5 +0,0 @@
-source "http://rubygems.org"
-
-gem "rake"
-gem "therubyracer", ">= 0.9.8", "< 0.11"
-gem "rspec"

Gemfile.lock

@@ -1,24 +0,0 @@
-GEM
-  remote: http://rubygems.org/
-  specs:
-    diff-lcs (1.1.3)
-    libv8 (3.3.10.4)
-    rake (10.0.3)
-    rspec (2.12.0)
-      rspec-core (~> 2.12.0)
-      rspec-expectations (~> 2.12.0)
-      rspec-mocks (~> 2.12.0)
-    rspec-core (2.12.2)
-    rspec-expectations (2.12.1)
-      diff-lcs (~> 1.1.3)
-    rspec-mocks (2.12.1)
-    therubyracer (0.10.2)
-      libv8 (~> 3.3.10)
-
-PLATFORMS
-  ruby
-
-DEPENDENCIES
-  rake
-  rspec
-  therubyracer (>= 0.9.8, < 0.11)

LICENSE

@@ -1,4 +1,4 @@
-Copyright (C) 2011 by Yehuda Katz
+Copyright (C) 2011-2019 by Yehuda Katz
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.markdown

@@ -1,317 +0,0 @@
-[![Build Status](https://secure.travis-ci.org/wycats/handlebars.js.png)](http://travis-ci.org/wycats/handlebars.js)
-
-Handlebars.js
-=============
-
-Handlebars.js is an extension to the [Mustache templating language](http://mustache.github.com/) created by Chris Wanstrath. Handlebars.js and Mustache are both logicless templating languages that keep the view and the code separated like we all know they should be.
-
-Checkout the official Handlebars docs site at [http://www.handlebarsjs.com](http://www.handlebarsjs.com).
-
-
-Installing
-----------
-Installing Handlebars is easy. Simply [download the package from GitHub](https://github.com/wycats/handlebars.js/archives/master) and add it to your web pages (you should usually use the most recent version).
-
-Usage
------
-In general, the syntax of Handlebars.js templates is a superset of Mustache templates. For basic syntax, check out the [Mustache manpage](http://mustache.github.com/mustache.5.html).
-
-Once you have a template, use the Handlebars.compile method to compile the template into a function. The generated function takes a context argument, which will be used to render the template.
-
-```js
-var source = "<p>Hello, my name is {{name}}. I am from {{hometown}}. I have " +
-             "{{kids.length}} kids:</p>" +
-             "<ul>{{#kids}}<li>{{name}} is {{age}}</li>{{/kids}}</ul>";
-var template = Handlebars.compile(source);
-
-var data = { "name": "Alan", "hometown": "Somewhere, TX",
-             "kids": [{"name": "Jimmy", "age": "12"}, {"name": "Sally", "age": "4"}]};
-var result = template(data);
-
-// Would render:
-// <p>Hello, my name is Alan. I am from Somewhere, TX. I have 2 kids:</p>
-// <ul>
-//   <li>Jimmy is 12</li>
-//   <li>Sally is 4</li>
-// </ul>
-```
-
-
-Registering Helpers
--------------------
-
-You can register helpers that Handlebars will use when evaluating your
-template. Here's an example, which assumes that your objects have a URL
-embedded in them, as well as the text for a link:
-
-```js
-Handlebars.registerHelper('link_to', function(context) {
-  return "<a href='" + context.url + "'>" + context.body + "</a>";
-});
-
-var context = { posts: [{url: "/hello-world", body: "Hello World!"}] };
-var source = "<ul>{{#posts}}<li>{{{link_to this}}}</li>{{/posts}}</ul>"
-
-var template = Handlebars.compile(source);
-template(context);
-
-// Would render:
-//
-// <ul>
-//   <li><a href='/hello-world'>Hello World!</a></li>
-// </ul>
-```
-
-Escaping
---------
-
-By default, the `{{expression}}` syntax will escape its contents. This
-helps to protect you against accidental XSS problems caused by malicious
-data passed from the server as JSON.
-
-To explicitly *not* escape the contents, use the triple-mustache
-(`{{{}}}`). You have seen this used in the above example.
-
-
-Differences Between Handlebars.js and Mustache
-----------------------------------------------
-Handlebars.js adds a couple of additional features to make writing templates easier and also changes a tiny detail of how partials work.
-
-### Paths
-
-Handlebars.js supports an extended expression syntax that we call paths. Paths are made up of typical expressions and . characters. Expressions allow you to not only display data from the current context, but to display data from contexts that are descendents and ancestors of the current context.
-
-To display data from descendent contexts, use the `.` character. So, for example, if your data were structured like:
-
-```js
-var data = {"person": { "name": "Alan" }, company: {"name": "Rad, Inc." } };
-```
-
-you could display the person's name from the top-level context with the following expression:
-
-```
-{{person.name}}
-```
-
-You can backtrack using `../`. For example, if you've already traversed into the person object you could still display the company's name with an expression like `{{../company.name}}`, so:
-
-```
-{{#person}}{{name}} - {{../company.name}}{{/person}}
-```
-
-would render:
-
-```
-Alan - Rad, Inc.
-```
-
-### Strings
-
-When calling a helper, you can pass paths or Strings as parameters. For
-instance:
-
-```js
-Handlebars.registerHelper('link_to', function(title, context) {
-  return "<a href='/posts" + context.url + "'>" + title + "!</a>"
-});
-
-var context = { posts: [{url: "/hello-world", body: "Hello World!"}] };
-var source = '<ul>{{#posts}}<li>{{{link_to "Post" this}}}</li>{{/posts}}</ul>'
-
-var template = Handlebars.compile(source);
-template(context);
-
-// Would render:
-//
-// <ul>
-//   <li><a href='/posts/hello-world'>Post!</a></li>
-// </ul>
-```
-
-When you pass a String as a parameter to a helper, the literal String
-gets passed to the helper function.
-
-
-### Block Helpers
-
-Handlebars.js also adds the ability to define block helpers. Block helpers are functions that can be called from anywhere in the template. Here's an example:
-
-```js
-var source = "<ul>{{#people}}<li>{{#link}}{{name}}{{/link}}</li>{{/people}}</ul>";
-Handlebars.registerHelper('link', function(options) {
-  return '<a href="/people/' + this.id + '">' + options.fn(this) + '</a>';
-});
-var template = Handlebars.compile(source);
-
-var data = { "people": [
-    { "name": "Alan", "id": 1 },
-    { "name": "Yehuda", "id": 2 }
-  ]};
-template(data);
-
-// Should render:
-// <ul>
-//   <li><a href="/people/1">Alan</a></li>
-//   <li><a href="/people/2">Yehuda</a></li>
-// </ul>
-```
-
-Whenever the block helper is called it is given two parameters, the argument that is passed to the helper, or the current context if no argument is passed and the compiled contents of the block. Inside of the block helper the value of `this` is the current context, wrapped to include a method named `__get__` that helps translate paths into values within the helpers.
-
-### Partials
-
-You can register additional templates as partials, which will be used by
-Handlebars when it encounters a partial (`{{> partialName}}`). Partials
-can either be String templates or compiled template functions. Here's an
-example:
-
-```js
-var source = "<ul>{{#people}}<li>{{> link}}</li>{{/people}}</ul>";
-
-Handlebars.registerPartial('link', '<a href="/people/{{id}}">{{name}}</a>')
-var template = Handlebars.compile(source);
-
-var data = { "people": [
-    { "name": "Alan", "id": 1 },
-    { "name": "Yehuda", "id": 2 }
-  ]};
-
-template(data);
-
-// Should render:
-// <ul>
-//   <li><a href="/people/1">Alan</a></li>
-//   <li><a href="/people/2">Yehuda</a></li>
-// </ul>
-```
-
-### Comments
-
-You can add comments to your templates with the following syntax:
-
-```js
-{{! This is a comment }}
-```
-
-You can also use real html comments if you want them to end up in the output.
-
-```html
-<div>
-    {{! This comment will not end up in the output }}
-    <!-- This comment will show up in the output -->
-</div>
-```
-
-
-Precompiling Templates
-----------------------
-
-Handlebars allows templates to be precompiled and included as javascript
-code rather than the handlebars template allowing for faster startup time.
-
-### Installation
-The precompiler script may be installed via npm using the `npm install -g handlebars`
-command.
-
-### Usage
-
-<pre>
-Precompile handlebar templates.
-Usage: handlebars template...
-
-Options:
-  -a, --amd        Create an AMD format function (allows loading with RequireJS)         [boolean]
-  -f, --output     Output File                                                           [string]
-  -k, --known      Known helpers                                                         [string]
-  -o, --knownOnly  Known helpers only                                                    [boolean]
-  -m, --min        Minimize output                                                       [boolean]
-  -s, --simple     Output template function only.                                        [boolean]
-  -r, --root       Template root. Base value that will be stripped from template names.  [string]
-</pre>
-
-If using the precompiler's normal mode, the resulting templates will be stored
-to the `Handlebars.templates` object using the relative template name sans the
-extension. These templates may be executed in the same manner as templates.
-
-If using the simple mode the precompiler will generate a single javascript method.
-To execute this method it must be passed to the using the `Handlebars.template`
-method and the resulting object may be as normal.
-
-### Optimizations
-
-- Rather than using the full _handlebars.js_ library, implementations that
-  do not need to compile templates at runtime may include _handlebars.runtime.js_
-  whose min+gzip size is approximately 1k.
-- If a helper is known to exist in the target environment they may be defined
-  using the `--known name` argument may be used to optimize accesses to these
-  helpers for size and speed.
-- When all helpers are known in advance the `--knownOnly` argument may be used
-  to optimize all block helper references.
-
-
-Performance
------------
-
-In a rough performance test, precompiled Handlebars.js templates (in the original version of Handlebars.js) rendered in about half the time of Mustache templates. It would be a shame if it were any other way, since they were precompiled, but the difference in architecture does have some big performance advantages. Justin Marney, a.k.a. [gotascii](http://github.com/gotascii), confirmed that with an [independent test](http://sorescode.com/2010/09/12/benchmarks.html). The rewritten Handlebars (current version) is faster than the old version, and we will have some benchmarks in the near future.
-
-
-Building
---------
-
-To build handlebars, just run `rake release`, and you will get two files
-in the `dist` directory.
-
-
-Upgrading
----------
-
-When upgrading from the Handlebars 0.9 series, be aware that the
-signature for passing custom helpers or partials to templates has
-changed.
-
-Instead of:
-
-```js
-template(context, helpers, partials, [data])
-```
-
-Use:
-
-```js
-template(context, {helpers: helpers, partials: partials, data: data})
-```
-
-Known Issues
-------------
-* Handlebars.js can be cryptic when there's an error while rendering.
-* Using a variable, helper, or partial named `class` causes errors in IE browsers. (Instead, use `className`)
-
-Handlebars in the Wild
------------------
-* [jblotus](http://github.com/jblotus) created [http://tryhandlebarsjs.com](http://tryhandlebarsjs.com) for anyone who would
-like to try out Handlebars.js in their browser.
-* Don Park wrote an Express.js view engine adapter for Handlebars.js called [hbs](http://github.com/donpark/hbs).
-* [sammy.js](http://github.com/quirkey/sammy) by Aaron Quint, a.k.a. quirkey, supports Handlebars.js as one of its template plugins.
-* [SproutCore](http://www.sproutcore.com) uses Handlebars.js as its main templating engine, extending it with automatic data binding support.
-* [Ember.js](http://www.emberjs.com) makes Handlebars.js the primary way to structure your views, also with automatic data binding support.
-* Les Hill (@leshill) wrote a Rails Asset Pipeline gem named [handlebars_assets](http://github.com/leshill/handlebars_assets).
-
-Helping Out
------------
-To build Handlebars.js you'll need a few things installed.
-
-* Node.js
-* Jison, for building the compiler - `npm install jison`
-* Ruby
-* therubyracer, for running tests - `gem install therubyracer`
-* rspec, for running tests - `gem install rspec`
-
-There's a Gemfile in the repo, so you can run `bundle` to install rspec and therubyracer if you've got bundler installed.
-
-To build Handlebars.js from scratch, you'll want to run `rake compile` in the root of the project. That will build Handlebars and output the results to the dist/ folder. To run tests, run `rake spec`. You can also run our set of benchmarks with `rake bench`.
-
-If you notice any problems, please report them to the GitHub issue tracker at [http://github.com/wycats/handlebars.js/issues](http://github.com/wycats/handlebars.js/issues). Feel free to contact commondream or wycats through GitHub with any other questions or feature requests. To submit changes fork the project and send a pull request.
-
-License
--------
-Handlebars.js is released under the MIT license.

README.md

@@ -0,0 +1,198 @@
+[![CI Build Status](https://github.com/handlebars-lang/handlebars.js/actions/workflows/ci.yml/badge.svg)](https://github.com/handlebars-lang/handlebars.js/actions/workflows/ci.yml)
+[![jsDelivr Hits](https://data.jsdelivr.com/v1/package/npm/handlebars/badge?style=rounded)](https://www.jsdelivr.com/package/npm/handlebars)
+[![npm downloads](https://badgen.net/npm/dm/handlebars)](https://www.npmjs.com/package/handlebars)
+[![npm version](https://badgen.net/npm/v/handlebars)](https://www.npmjs.com/package/handlebars)
+[![Bundle size](https://badgen.net/bundlephobia/minzip/handlebars?label=minified%20%2B%20gzipped)](https://bundlephobia.com/package/handlebars)
+[![Install size](https://packagephobia.com/badge?p=handlebars)](https://packagephobia.com/result?p=handlebars)
+
+# Handlebars.js
+
+Handlebars provides the power necessary to let you build **semantic templates** effectively with no frustration.
+Handlebars is largely compatible with Mustache templates. In most cases it is possible to swap out Mustache with Handlebars and continue using your current templates.
+
+Checkout the official Handlebars docs site at
+[handlebarsjs.com](https://handlebarsjs.com) and try our [live demo](https://handlebarsjs.com/playground.html).
+
+## Installing
+
+See our [installation documentation](https://handlebarsjs.com/guide/installation/).
+
+## Usage
+
+In general, the syntax of Handlebars.js templates is a superset
+of Mustache templates. For basic syntax, check out the [Mustache
+manpage](https://mustache.github.io/mustache.5.html).
+
+Once you have a template, use the `Handlebars.compile` method to compile
+the template into a function. The generated function takes a context
+argument, which will be used to render the template.
+
+```js
+var source =
+  '<p>Hello, my name is {{name}}. I am from {{hometown}}. I have ' +
+  '{{kids.length}} kids:</p>' +
+  '<ul>{{#kids}}<li>{{name}} is {{age}}</li>{{/kids}}</ul>';
+var template = Handlebars.compile(source);
+
+var data = {
+  name: 'Alan',
+  hometown: 'Somewhere, TX',
+  kids: [
+    { name: 'Jimmy', age: '12' },
+    { name: 'Sally', age: '4' },
+  ],
+};
+var result = template(data);
+
+// Would render:
+// <p>Hello, my name is Alan. I am from Somewhere, TX. I have 2 kids:</p>
+// <ul>
+//   <li>Jimmy is 12</li>
+//   <li>Sally is 4</li>
+// </ul>
+```
+
+Full documentation and more examples are at [handlebarsjs.com](https://handlebarsjs.com/).
+
+## Precompiling Templates
+
+Handlebars allows templates to be precompiled and included as javascript code rather than the handlebars template allowing for faster startup time. Full details are located [here](https://handlebarsjs.com/guide/installation/precompilation.html).
+
+## Differences Between Handlebars.js and Mustache
+
+Handlebars.js adds a couple of additional features to make writing
+templates easier and also changes a tiny detail of how partials work.
+
+- [Nested Paths](https://handlebarsjs.com/guide/expressions.html#path-expressions)
+- [Helpers](https://handlebarsjs.com/guide/expressions.html#helpers)
+- [Block Expressions](https://handlebarsjs.com/guide/block-helpers.html#basic-blocks)
+- [Literal Values](https://handlebarsjs.com/guide/expressions.html#literal-segments)
+- [Delimited Comments](https://handlebarsjs.com/guide/#template-comments)
+
+Block expressions have the same syntax as mustache sections but should not be confused with one another. Sections are akin to an implicit `each` or `with` statement depending on the input data and helpers are explicit pieces of code that are free to implement whatever behavior they like. The [mustache spec](https://mustache.github.io/mustache.5.html) defines the exact behavior of sections. In the case of name conflicts, helpers are given priority.
+
+### Compatibility
+
+There are a few Mustache behaviors that Handlebars does not implement.
+
+- Handlebars deviates from Mustache slightly in that it does not perform recursive lookup by default. The compile time `compat` flag must be set to enable this functionality. Users should note that there is a performance cost for enabling this flag. The exact cost varies by template, but it's recommended that performance sensitive operations should avoid this mode and instead opt for explicit path references.
+- The optional Mustache-style lambdas are not supported. Instead Handlebars provides its own lambda resolution that follows the behaviors of helpers.
+- Handlebars does not allow space between the opening `{{` and a command character such as `#`, `/` or `>`. The command character must immediately follow the braces, so for example `{{> partial }}` is allowed but `{{ > partial }}` is not.
+- Alternative delimiters are not supported.
+
+## Supported Environments
+
+Handlebars has been designed to work in any ECMAScript 2020 environment. This includes
+
+- Node.js
+- Chrome
+- Firefox
+- Safari
+- Edge
+
+If you need to support older environments, use Handlebars version 4.
+
+## Performance
+
+In a rough performance test, precompiled Handlebars.js templates (in
+the original version of Handlebars.js) rendered in about half the
+time of Mustache templates. It would be a shame if it were any other
+way, since they were precompiled, but the difference in architecture
+does have some big performance advantages. Justin Marney, a.k.a.
+[gotascii](http://github.com/gotascii), confirmed that with an
+[independent test](http://sorescode.com/2010/09/12/benchmarks.html). The
+rewritten Handlebars (current version) is faster than the old version,
+with many performance tests being 5 to 7 times faster than the Mustache equivalent.
+
+### Benchmarks
+
+The project includes a comprehensive benchmark suite (powered by [tinybench](https://github.com/tinylibs/tinybench)) that measures compilation, execution, precompilation, and end-to-end performance across templates of varying size and complexity.
+
+```bash
+# Run benchmarks (auto-labels with current git branch)
+npm run bench
+
+# Run with a custom label
+npm run bench -- --label my-optimization
+
+# Filter templates by name (regex, case-insensitive)
+npm run bench -- --grep "complex|recursive"
+
+# Run only specific sections (regex, case-insensitive)
+npm run bench -- --section precompil
+npm run bench -- --section "compilation|precompil"
+
+# Compare results
+npm run bench:compare
+
+# Or specify files explicitly
+npm run bench:compare -- bench/results/bench-*-main.md bench/results/bench-*-feat.md
+```
+
+Results are saved as timestamped Markdown files in `bench/results/`. Each report includes ops/sec, avg latency, p50/p75/p99 percentiles, and sample counts.
+
+Typical workflow for comparing branches:
+
+```bash
+git checkout main && npm run bench
+git checkout my-feature && npm run bench
+npm run bench:compare
+```
+
+When run without arguments, `bench:compare` auto-selects two result files: if a file labelled "main" exists it is always used as the baseline, otherwise the older file is the baseline. The comparison uses p75 latency for the diff to filter outliers, and marks changes with `!` (>2%) and `!!` (>5%).
+
+## Upgrading
+
+See [release-notes.md](https://github.com/handlebars-lang/handlebars.js/blob/master/release-notes.md) for upgrade notes.
+
+If you are using Handlebars in production, please regularly look for issues labeled
+[possibly breaking](https://github.com/handlebars-lang/handlebars.js/issues?q=is%3Aopen+is%3Aissue+label%3A%22possibly+breaking%22).
+If this label is applied to an issue, it means that the requested change is probably not a breaking change,
+but since Handlebars is widely in use by a lot of people, there's always a chance that it breaks somebody's build.
+
+## Known Issues
+
+See [FAQ.md](https://github.com/handlebars-lang/handlebars.js/blob/master/FAQ.md) for known issues and common pitfalls.
+
+## Handlebars in the Wild
+
+- [apiDoc](https://github.com/apidoc/apidoc) apiDoc uses handlebars as parsing engine for api documentation view generation.
+- [Assemble](https://assemble.io), by [@jonschlinkert](https://github.com/jonschlinkert) and [@doowb](https://github.com/doowb), is a static site generator that uses Handlebars.js as its template engine.
+- [CoSchedule](https://coschedule.com) An editorial calendar for WordPress that uses Handlebars.js.
+- [Ember.js](https://www.emberjs.com) makes Handlebars.js the primary way to structure your views, also with automatic data binding support.
+- [express-handlebars](https://github.com/express-handlebars/express-handlebars) A Handlebars view engine for Express which doesn't suck.
+- [express-hbs](https://github.com/TryGhost/express-hbs) Express Handlebars template engine with inheritance, partials, i18n and async helpers.
+- [Ghost](https://ghost.org/) Just a blogging platform.
+- [handlebars-action](https://github.com/marketplace/actions/handlebars-action) A GitHub action to transform files in your repository with Handlebars templating.
+- [handlebars_assets](https://github.com/leshill/handlebars_assets) A Rails Asset Pipeline gem from Les Hill (@leshill).
+- [handlebars-helpers](https://github.com/assemble/handlebars-helpers) is an extensive library with 100+ handlebars helpers.
+- [handlebars-layouts](https://github.com/shannonmoeller/handlebars-layouts) is a set of helpers which implement extensible and embeddable layout blocks as seen in other popular templating languages.
+- [handlebars-loader](https://github.com/pcardune/handlebars-loader) A handlebars template loader for webpack.
+- [handlebars-wax](https://github.com/shannonmoeller/handlebars-wax) The missing Handlebars API. Effortless registration of data, partials, helpers, and decorators using file-system globs, modules, and plain-old JavaScript objects.
+- [hbs](https://github.com/pillarjs/hbs) An Express.js view engine adapter for Handlebars.js, from Don Park.
+- [html-bundler-webpack-plugin](https://github.com/webdiscus/html-bundler-webpack-plugin) The webpack plugin to compile templates, [supports Handlebars](https://github.com/webdiscus/html-bundler-webpack-plugin#using-template-handlebars).
+- [incremental-bars](https://github.com/atomictag/incremental-bars) adds support for [incremental-dom](https://github.com/google/incremental-dom) as template target to Handlebars.
+- [jQuery plugin](https://71104.github.io/jquery-handlebars/) allows you to use Handlebars.js with [jQuery](http://jquery.com/).
+- [just-handlebars-helpers](https://github.com/leapfrogtechnology/just-handlebars-helpers) A fully tested lightweight package with common Handlebars helpers.
+- [koa-hbs](https://github.com/jwilm/koa-hbs) [koa](https://github.com/koajs/koa) generator based renderer for Handlebars.js.
+- [Marionette.Handlebars](https://github.com/hashchange/marionette.handlebars) adds support for Handlebars and Mustache templates to Marionette.
+- [openVALIDATION](https://github.com/openvalidation/openvalidation) a natural language compiler for validation rules. Generates program code in Java, JavaScript, C#, Python and Rust with handlebars.
+- [Plop](https://plopjs.com/) is a micro-generator framework that makes it easy to create files with a level of uniformity.
+- [promised-handlebars](https://github.com/nknapp/promised-handlebars) is a wrapper for Handlebars that allows helpers to return Promises.
+- [sammy.js](https://github.com/quirkey/sammy) by Aaron Quint, a.k.a. quirkey, supports Handlebars.js as one of its template plugins.
+- [Swag](https://github.com/elving/swag) by [@elving](https://github.com/elving) is a growing collection of helpers for handlebars.js. Give your handlebars.js templates some swag son!
+- [SproutCore](https://www.sproutcore.com) uses Handlebars.js as its main templating engine, extending it with automatic data binding support.
+- [vite-plugin-handlebars](https://github.com/alexlafroscia/vite-plugin-handlebars) A package for Vite 2. Allows for running your HTML files through the Handlebars compiler.
+- [YUI](https://yuilibrary.com/yui/docs/handlebars/) implements a port of handlebars.
+
+## External Resources
+
+- [Gist about Synchronous and asynchronous loading of external handlebars templates](https://gist.github.com/2287070)
+
+Have a project using Handlebars? Send us a [pull request][pull-request]!
+
+## License
+
+Handlebars.js is released under the MIT license.
+
+[pull-request]: https://github.com/handlebars-lang/handlebars.js/pull/new/master

Rakefile

@@ -1,109 +0,0 @@
-require "rubygems"
-require "bundler/setup"
-
-def compile_parser
-  system "./node_modules/.bin/jison -m js src/handlebars.yy src/handlebars.l"
-  if $?.success?
-    File.open("lib/handlebars/compiler/parser.js", "w") do |file|
-      file.puts File.read("src/parser-prefix.js") + File.read("handlebars.js") + File.read("src/parser-suffix.js")
-    end
-
-    sh "rm handlebars.js"
-  else
-    puts "Failed to run Jison."
-  end
-end
-
-file "lib/handlebars/compiler/parser.js" => ["src/handlebars.yy","src/handlebars.l"] do
-  if File.exists?('./node_modules/jison')
-    compile_parser
-  else
-    puts "Jison is not installed. Trying `npm install jison`."
-    sh "npm install"
-    compile_parser
-  end
-end
-
-task :compile => "lib/handlebars/compiler/parser.js"
-
-desc "run the spec suite"
-task :spec => [:release] do
-  rc = system "rspec -cfs spec"
-  fail "rspec spec failed with exit code #{$?.exitstatus}" if (rc.nil? || ! rc || $?.exitstatus != 0)
-end
-
-desc "run the npm test suite"
-task :npm_test => [:release] do
-  rc = system "npm test"
-  fail "npm test failed with exit code #{$?.exitstatus}" if (rc.nil? || ! rc || $?.exitstatus != 0)
-end
-
-task :default => [:compile, :spec, :npm_test]
-
-def remove_exports(string)
-  match = string.match(%r{^// BEGIN\(BROWSER\)\n(.*)\n^// END\(BROWSER\)}m)
-  match ? match[1] : string
-end
-
-minimal_deps = %w(base compiler/parser compiler/base compiler/ast utils compiler/compiler runtime).map do |file|
-  "lib/handlebars/#{file}.js"
-end
-
-runtime_deps = %w(base utils runtime).map do |file|
-  "lib/handlebars/#{file}.js"
-end
-
-directory "dist"
-
-minimal_deps.unshift "dist"
-
-def build_for_task(task)
-  FileUtils.rm_rf("dist/*") if File.directory?("dist")
-  FileUtils.mkdir_p("dist")
-
-  contents = ["/*\n\n" + File.read('LICENSE') + "\n*/\n"]
-  task.prerequisites.each do |filename|
-    next if filename == "dist"
-
-    contents << "// #{filename}\n" + remove_exports(File.read(filename)) + ";"
-  end
-
-  File.open(task.name, "w") do |file|
-    file.puts contents.join("\n")
-  end
-end
-
-file "dist/handlebars.js" => minimal_deps do |task|
-  build_for_task(task)
-end
-
-file "dist/handlebars.runtime.js" => runtime_deps do |task|
-  build_for_task(task)
-end
-
-task :build => [:compile, "dist/handlebars.js"]
-task :runtime => [:compile, "dist/handlebars.runtime.js"]
-
-desc "build the build and runtime version of handlebars"
-task :release => [:build, :runtime]
-
-directory "vendor"
-
-desc "benchmark against dust.js and mustache.js"
-task :bench => "vendor" do
-  require "open-uri"
-
-  #if File.directory?("vendor/coffee")
-    #system "cd vendor/coffee && git pull"
-  #else
-    #system "git clone git://github.com/jashkenas/coffee-script.git vendor/coffee"
-  #end
-
-  #if File.directory?("vendor/eco")
-    #system "cd vendor/eco && git pull && npm update"
-  #else
-    #system "git clone git://github.com/sstephenson/eco.git vendor/eco && cd vendor/eco && npm update"
-  #end
-
-  system "node bench/handlebars.js"
-end

SECURITY.md

@@ -0,0 +1,15 @@
+# Security Policy
+
+We recommend always using the latest versions of Handlebars and its official companion libraries to ensure your application remains as secure as possible.
+
+## Supported Versions
+
+| Version | Supported          |
+| ------- | ------------------ |
+| 5.0.x   | :white_check_mark: |
+| 4.7.x   | :white_check_mark: |
+| < 4.7   | :x:                |
+
+## Reporting a Vulnerability
+
+To report a vulnerability, please visit https://github.com/handlebars-lang/handlebars.js/security.

bench/benchwarmer.js

@@ -1,149 +0,0 @@
-
-var Benchmark = require("benchmark");
-
-var BenchWarmer = function(names) {
-  this.benchmarks = [];
-  this.currentBenches = [];
-  this.names = [];
-  this.errors = {};
-};
-
-var print = require("sys").print;
-
-BenchWarmer.prototype = {
-  winners: function(benches) {
-    var result = Benchmark.filter(benches, function(bench) { return bench.cycles; });
-
-    if (result.length > 1) {
-      result.sort(function(a, b) { return b.compare(a); });
-      first = result[0];
-      last  = result[result.length - 1];
-
-      var winners = [];
-
-      Benchmark.each(result, function(bench) {
-        if (bench.compare(first) === 0) {
-          winners.push(bench);
-        }
-      });
-
-      return winners;
-    } else {
-      return result;
-    }
-  },
-  suite: function(suite, fn) {
-    this.suiteName = suite;
-    this.first = true;
-
-    var self = this;
-
-    fn(function(name, benchFn) {
-      self.push(name, benchFn);
-    });
-  },
-  push: function(name, fn) {
-    if(this.names.indexOf(name) == -1) {
-      this.names.push(name);
-    }
-
-    var first = this.first, suiteName = this.suiteName, self = this;
-    this.first = false;
-
-    var bench = new Benchmark(function() {
-      fn();
-    }, {
-      name: this.suiteName + ": " + name,
-      onComplete: function() {
-        if(first) { self.startLine(suiteName); }
-        self.writeBench(bench);
-        self.currentBenches.push(bench);
-      }, onError: function() {
-        self.errors[this.name] = this;
-      }
-    });
-
-    this.benchmarks.push(bench);
-  },
-  bench: function() {
-    var benchSize = 0, names = this.names, self = this, i, l;
-
-    for(i=0, l=names.length; i<l; i++) {
-      var name = names[i];
-
-      if(benchSize < name.length) { benchSize = name.length; }
-    }
-
-    this.nameSize = benchSize + 2;
-    this.benchSize = 20;
-    var horSize = 0;
-
-    this.startLine("ops/msec");
-    horSize = horSize + "ops/msec    ".length;
-    for(i=0, l=names.length; i<l; i++) {
-      print(names[i] + new Array(this.benchSize - names[i].length + 1).join(" "));
-      horSize = horSize + this.benchSize;
-    }
-
-    print("WINNER(S)");
-    horSize = horSize + "WINNER(S)".length;
-
-    print("\n" + new Array(horSize + 1).join("-"));
-
-    Benchmark.invoke(this.benchmarks, {
-      name: "run",
-      onComplete: function() {
-        var errors = false, prop, bench;
-        for(prop in self.errors) { if(self.errors.hasOwnProperty(prop)) { errors = true; break; } }
-
-        if(errors) {
-          print("\n\nErrors:\n");
-          for(prop in self.errors) {
-            if(self.errors.hasOwnProperty(prop)) {
-              bench = self.errors[prop];
-              print("\n" + bench.name + ":\n");
-              print(bench.error.message);
-              if(bench.error.stack) {
-                print(bench.error.stack.join("\n"));
-              }
-              print("\n");
-            }
-          }
-        }
-      }
-    });
-
-    print("\n");
-  },
-  startLine: function(name) {
-    var winners = Benchmark.map(this.winners(this.currentBenches), function(bench) {
-      return bench.name.split(": ")[1];
-    });
-
-    this.currentBenches = [];
-
-    print(winners.join(", "));
-    print("\n");
-    var padding = this.nameSize - name.length + 1;
-    name = name + new Array(padding).join(" ");
-    print(name);
-  },
-  writeBench: function(bench) {
-    var out;
-
-    if(!bench.error) {
-      var count = bench.hz,
-          moe   = count * bench.stats.rme / 100;
-
-      out = Math.round(count / 1000) + " ±" + Math.round(moe / 1000) + " (" + bench.cycles + ")";
-    } else {
-      out = "E";
-    }
-
-    var padding = this.benchSize - out.length + 1;
-    out = out + new Array(padding).join(" ");
-    print(out);
-  }
-};
-
-module.exports = BenchWarmer;

bench/handlebars.js

@@ -1,172 +0,0 @@
-var BenchWarmer = require("./benchwarmer");
-Handlebars = require("../lib/handlebars");
-
-var dust, Mustache, eco;
-
-try {
-  dust = require("dust");
-} catch (err) { /* NOP */ }
-
-try {
-  Mustache = require("mustache");
-} catch (err) { /* NOP */ }
-
-try {
-  var ecoExports = require("eco");
-  eco = function(str) {
-    return ecoExports(str);
-  }
-} catch (err) { /* NOP */ }
-
-var benchDetails = {
-  string: {
-    context: {},
-    handlebars: "Hello world",
-    dust: "Hello world",
-    mustache: "Hello world",
-    eco: "Hello world"
-  },
-  variables: {
-    context: {name: "Mick", count: 30},
-    handlebars:  "Hello {{name}}! You have {{count}} new messages.",
-    dust: "Hello {name}! You have {count} new messages.",
-    mustache: "Hello {{name}}! You have {{count}} new messages.",
-    eco: "Hello <%= @name %>! You have <%= @count %> new messages."
-  },
-  object: {
-    context:  { person: { name: "Larry", age: 45 } },
-    handlebars: "{{#with person}}{{name}}{{age}}{{/with}}",
-    dust: "{#person}{name}{age}{/person}",
-    mustache: "{{#person}}{{name}}{{age}}{{/person}}"
-  },
-  array: {
-    context:  { names: [{name: "Moe"}, {name: "Larry"}, {name: "Curly"}, {name: "Shemp"}] },
-    handlebars: "{{#each names}}{{name}}{{/each}}",
-    dust: "{#names}{name}{/names}",
-    mustache: "{{#names}}{{name}}{{/names}}",
-    eco: "<% for item in @names: %><%= item.name %><% end %>"
-  },
-  partial: {
-    context: { peeps: [{name: "Moe", count: 15}, {name: "Larry", count: 5}, {name: "Curly", count: 1}] },
-    partials: {
-      mustache: { variables: "Hello {{name}}! You have {{count}} new messages." },
-      handlebars: { variables: "Hello {{name}}! You have {{count}} new messages." }
-    },
-    handlebars: "{{#each peeps}}{{>variables}}{{/each}}",
-    dust: "{#peeps}{>variables/}{/peeps}",
-    mustache: "{{#peeps}}{{>variables}}{{/peeps}}"
-  },
-  recursion: {
-    context: { name: '1', kids: [{ name: '1.1', kids: [{name: '1.1.1', kids: []}] }] },
-    partials: {
-      mustache: { recursion: "{{name}}{{#kids}}{{>recursion}}{{/kids}}" },
-      handlebars: { recursion: "{{name}}{{#each kids}}{{>recursion}}{{/each}}" }
-    },
-    handlebars: "{{name}}{{#each kids}}{{>recursion}}{{/each}}",
-    dust: "{name}{#kids}{>recursion:./}{/kids}",
-    mustache: "{{name}}{{#kids}}{{>recursion}}{{/kids}}"
-  },
-  complex: {
-    handlebars: "<h1>{{header}}</h1>{{#if items}}<ul>{{#each items}}{{#if current}}" +
-                "<li><strong>{{name}}</strong></li>{{^}}" +
-                "<li><a href=\"{{url}}\">{{name}}</a></li>{{/if}}" +
-                "{{/each}}</ul>{{^}}<p>The list is empty.</p>{{/if}}",
-
-    dust:       "<h1>{header}</h1>\n"                             +
-                "{?items}\n"                                      +
-                "  <ul>\n"                                        +
-                "    {#items}\n"                                  +
-                "      {#current}\n"                              +
-                "        <li><strong>{name}</strong></li>\n"      +
-                "      {:else}\n"                                 +
-                "        <li><a href=\"{url}\">{name}</a></li>\n" +
-                "      {/current}\n"                              +
-                "    {/items}\n"                                  +
-                "  </ul>\n"                                       +
-                "{:else}\n"                                       +
-                "  <p>The list is empty.</p>\n"                   +
-                "{/items}",
-    context: {
-               header: function() {
-                 return "Colors";
-               },
-               items: [
-                 {name: "red", current: true, url: "#Red"},
-                 {name: "green", current: false, url: "#Green"},
-                 {name: "blue", current: false, url: "#Blue"}
-               ]
-             }
-  }
-
-};
-
-handlebarsTemplates = {};
-ecoTemplates = {};
-
-var warmer = new BenchWarmer();
-
-var makeSuite = function(name) {
-  warmer.suite(name, function(bench) {
-    var templateName = name;
-    var details = benchDetails[templateName];
-    var mustachePartials = details.partials && details.partials.mustache;
-    var mustacheSource = details.mustache;
-    var context = details.context;
-
-    var error = function() { throw new Error("EWOT"); };
-
-    if (dust) {
-      bench("dust", function() {
-        dust.render(templateName, context, function(err, out) { });
-      });
-    }
-
-    bench("handlebars", function() {
-      handlebarsTemplates[templateName](context);
-    });
-
-    if (eco) {
-      if(ecoTemplates[templateName]) {
-        bench("eco", function() {
-          ecoTemplates[templateName](context);
-        });
-      } else {
-        bench("eco", error);
-      }
-    }
-
-    if (Mustache && mustacheSource) {
-      bench("mustache", function() {
-        Mustache.to_html(mustacheSource, context, mustachePartials);
-      });
-    } else {
-      bench("mustache", error);
-    }
-  });
-}
-
-for(var name in benchDetails) {
-  if(benchDetails.hasOwnProperty(name)) {
-    if (dust) {
-      dust.loadSource(dust.compile(benchDetails[name].dust, name));
-    }
-    handlebarsTemplates[name] = Handlebars.compile(benchDetails[name].handlebars);
-
-    if (eco && benchDetails[name].eco) {
-      ecoTemplates[name] = eco(benchDetails[name].eco);
-    }
-
-    var partials = benchDetails[name].partials;
-    if(partials) {
-      for(var partialName in partials.handlebars) {
-        if(partials.handlebars.hasOwnProperty(partialName)) {
-          Handlebars.registerPartial(partialName, partials.handlebars[partialName]);
-        }
-      }
-    }
-
-    makeSuite(name);
-  }
-}
-
-warmer.bench();

bin/handlebars

@@ -1,193 +0,0 @@
-#!/usr/bin/env node
-
-var optimist = require('optimist')
-    .usage('Precompile handlebar templates.\nUsage: $0 template...', {
-      'f': {
-        'type': 'string',
-        'description': 'Output File',
-        'alias': 'output'
-      },
-      'a': {
-        'type': 'boolean',
-        'description': 'Exports amd style (require.js)',
-        'alias': 'amd'
-      },
-      'c': {
-        'type': 'string',
-        'description': 'Exports CommonJS style, path to Handlebars module',
-        'alias': 'commonjs',
-        'default': null
-      },
-      'h': {
-        'type': 'string',
-        'description': 'Path to handlebar.js (only valid for amd-style)',
-        'alias': 'handlebarPath',
-		    'default': ''
-      },
-      'k': {
-        'type': 'string',
-        'description': 'Known helpers',
-        'alias': 'known'
-      },
-      'o': {
-        'type': 'boolean',
-        'description': 'Known helpers only',
-        'alias': 'knownOnly'
-      },
-      'm': {
-        'type': 'boolean',
-        'description': 'Minimize output',
-        'alias': 'min'
-      },
-      'n': {
-        'type': 'string',
-        'description': 'Template namespace',
-        'alias': 'namespace',
-        'default': 'Handlebars.templates'
-      },
-      's': {
-        'type': 'boolean',
-        'description': 'Output template function only.',
-        'alias': 'simple'
-      },
-      'r': {
-        'type': 'string',
-        'description': 'Template root. Base value that will be stripped from template names.',
-        'alias': 'root'
-      },
-      'p' : {
-        'type': 'boolean',
-        'description': 'Compiling a partial template',
-        'alias': 'partial'
-      },
-      'd' : {
-        'type': 'boolean',
-        'description': 'Include data when compiling',
-        'alias': 'data'
-      }
-    })
-
-    .check(function(argv) {
-      var template = [0];
-      if (!argv._.length) {
-        throw 'Must define at least one template or directory.';
-      }
-
-      argv._.forEach(function(template) {
-        try {
-          fs.statSync(template);
-        } catch (err) {
-          throw 'Unable to open template file "' + template + '"';
-        }
-      });
-    })
-    .check(function(argv) {
-      if (argv.simple && argv.min) {
-        throw 'Unable to minimze simple output';
-      }
-      if (argv.simple && (argv._.length !== 1 || fs.statSync(argv._[0]).isDirectory())) {
-        throw 'Unable to output multiple templates in simple mode';
-      }
-    });
-
-var fs = require('fs'),
-    handlebars = require('../lib/handlebars'),
-    basename = require('path').basename,
-    uglify = require('uglify-js');
-
-var argv = optimist.argv,
-    template = argv._[0];
-
-// Convert the known list into a hash
-var known = {};
-if (argv.known && !Array.isArray(argv.known)) {
-  argv.known = [argv.known];
-}
-if (argv.known) {
-  for (var i = 0, len = argv.known.length; i < len; i++) {
-    known[argv.known[i]] = true;
-  }
-}
-
-var output = [];
-if (!argv.simple) {
-  if (argv.amd) {
-    output.push('define([\'' + argv.handlebarPath + 'handlebars\'], function(Handlebars) {\n');
-  } else if (argv.commonjs) {
-    output.push('var Handlebars = require("' + argv.commonjs + '");');
-  } else {
-    output.push('(function() {\n');
-  }
-  output.push('  var template = Handlebars.template, templates = ');
-  output.push(argv.namespace);
-  output.push(' = ');
-  output.push(argv.namespace);
-  output.push(' || {};\n');
-}
-function processTemplate(template, root) {
-  var path = template,
-      stat = fs.statSync(path);
-  if (stat.isDirectory()) {
-    fs.readdirSync(template).map(function(file) {
-      var path = template + '/' + file;
-
-      if (/\.handlebars$/.test(path) || fs.statSync(path).isDirectory()) {
-        processTemplate(path, root || template);
-      }
-    });
-  } else {
-    var data = fs.readFileSync(path, 'utf8');
-
-    var options = {
-      knownHelpers: known,
-      knownHelpersOnly: argv.o
-    };
-
-    if (argv.data) {
-      options.data = true;
-    }
-
-    // Clean the template name
-    if (!root) {
-      template = basename(template);
-    } else if (template.indexOf(root) === 0) {
-      template = template.substring(root.length+1);
-    }
-    template = template.replace(/\.handlebars$/, '');
-
-    if (argv.simple) {
-      output.push(handlebars.precompile(data, options) + '\n');
-    } else if (argv.partial) {
-      output.push('Handlebars.partials[\'' + template + '\'] = template(' + handlebars.precompile(data, options) + ');\n');
-    } else {
-      output.push('templates[\'' + template + '\'] = template(' + handlebars.precompile(data, options) + ');\n');
-    }
-  }
-}
-
-argv._.forEach(function(template) {
-  processTemplate(template, argv.root);
-});
-
-// Output the content
-if (!argv.simple) {
-  if (argv.amd) {
-    output.push('});');
-  } else if (!argv.commonjs) {
-    output.push('})();');
-  }
-}
-output = output.join('');
-
-if (argv.min) {
-  var ast = uglify.parser.parse(output);
-  ast = uglify.uglify.ast_mangle(ast);
-  ast = uglify.uglify.ast_squeeze(ast);
-  output = uglify.uglify.gen_code(ast);
-}
-
-if (argv.output) {
-  fs.writeFileSync(argv.output, output, 'utf8');
-} else {
-  console.log(output);
-}

bin/handlebars.mjs

@@ -0,0 +1,136 @@
+#!/usr/bin/env node
+
+import { createRequire } from 'node:module';
+import yargs from 'yargs';
+
+const require = createRequire(import.meta.url);
+const Precompiler = require('../dist/cjs/precompiler');
+
+const parser = yargs(process.argv.slice(2))
+  .usage('Precompile handlebar templates.\nUsage: $0 [template|directory]...')
+  .help(false)
+  .version(false)
+  .option('f', {
+    type: 'string',
+    description: 'Output File',
+    alias: 'output',
+  })
+  .option('map', {
+    type: 'string',
+    description: 'Source Map File',
+  })
+  .option('a', {
+    type: 'boolean',
+    description: 'Exports amd style (require.js)',
+    alias: 'amd',
+  })
+  .option('c', {
+    type: 'string',
+    description: 'Exports CommonJS style, path to Handlebars module',
+    alias: 'commonjs',
+    default: null,
+  })
+  .option('h', {
+    type: 'string',
+    description: 'Path to handlebar.js (only valid for amd-style)',
+    alias: 'handlebarPath',
+    default: '',
+  })
+  .option('k', {
+    type: 'string',
+    description: 'Known helpers',
+    alias: 'known',
+  })
+  .option('o', {
+    type: 'boolean',
+    description: 'Known helpers only',
+    alias: 'knownOnly',
+  })
+  .option('m', {
+    type: 'boolean',
+    description: 'Minimize output',
+    alias: 'min',
+  })
+  .option('n', {
+    type: 'string',
+    description: 'Template namespace',
+    alias: 'namespace',
+    default: 'Handlebars.templates',
+  })
+  .option('s', {
+    type: 'boolean',
+    description: 'Output template function only.',
+    alias: 'simple',
+  })
+  .option('N', {
+    type: 'string',
+    description:
+      'Name of passed string templates. Optional if running in a simple mode. Required when operating on multiple templates.',
+    alias: 'name',
+  })
+  .option('i', {
+    type: 'string',
+    description:
+      'Generates a template from the passed CLI argument.\n"-" is treated as a special value and causes stdin to be read for the template value.',
+    alias: 'string',
+  })
+  .option('r', {
+    type: 'string',
+    description:
+      'Template root. Base value that will be stripped from template names.',
+    alias: 'root',
+  })
+  .option('p', {
+    type: 'boolean',
+    description: 'Compiling a partial template',
+    alias: 'partial',
+  })
+  .option('d', {
+    type: 'boolean',
+    description: 'Include data when compiling',
+    alias: 'data',
+  })
+  .option('e', {
+    type: 'string',
+    description: 'Template extension.',
+    alias: 'extension',
+    default: 'handlebars',
+  })
+  .option('b', {
+    type: 'boolean',
+    description:
+      'Removes the BOM (Byte Order Mark) from the beginning of the templates.',
+    alias: 'bom',
+  })
+  .option('v', {
+    type: 'boolean',
+    description: 'Prints the current compiler version',
+    alias: 'version',
+  })
+  .option('help', {
+    type: 'boolean',
+    description: 'Outputs this message',
+  })
+  .wrap(120);
+
+const argv = parser.parseSync();
+argv.files = argv._;
+delete argv._;
+
+Precompiler.loadTemplates(argv, function (err, opts) {
+  if (err) {
+    throw err;
+  }
+
+  if (opts.help || (!opts.templates.length && !opts.version)) {
+    parser.showHelp('log');
+  } else {
+    // cli() is async (returns a Promise), so errors would become unhandled
+    // rejections. Re-throw via nextTick to surface them as uncaught exceptions.
+    Promise.resolve(Precompiler.cli(opts)).catch((error) => {
+      process.nextTick(() => {
+        throw error;
+      });
+    });
+  }
+});

components/bower.json

@@ -0,0 +1,7 @@
+{
+  "name": "handlebars",
+  "version": "5.0.0-alpha.1",
+  "main": "handlebars.js",
+  "license": "MIT",
+  "dependencies": {}
+}

components/component.json

@@ -0,0 +1,7 @@
+{
+  "name": "handlebars",
+  "repo": "components/handlebars.js",
+  "version": "1.0.0",
+  "main": "handlebars.js",
+  "scripts": ["handlebars.js"]
+}

components/composer.json

@@ -0,0 +1,35 @@
+{
+  "name": "components/handlebars.js",
+  "description": "Handlebars.js and Mustache are both logicless templating languages that keep the view and the code separated like we all know they should be.",
+  "homepage": "http://handlebarsjs.com",
+  "license": "MIT",
+  "type": "component",
+  "keywords": [
+    "handlebars",
+    "mustache",
+    "html"
+  ],
+  "authors": [
+    {
+      "name": "Chris Wanstrath",
+      "homepage": "http://chriswanstrath.com"
+    }
+  ],
+  "require": {
+    "robloach/component-installer": "*"
+  },
+  "extra": {
+    "component": {
+      "name": "handlebars",
+      "scripts": [
+        "handlebars.js"
+      ],
+      "files": [
+        "handlebars.runtime.js"
+      ],
+      "shim": {
+        "exports": "Handlebars"
+      }
+    }
+  }
+}

components/handlebars-source.gemspec

@@ -0,0 +1,22 @@
+# -*- encoding: utf-8 -*-
+require 'json'
+
+package = JSON.parse(File.read('bower.json'))
+
+Gem::Specification.new do |gem|
+  gem.name          = "handlebars-source"
+  gem.authors       = ["Yehuda Katz"]
+  gem.email         = ["wycats@gmail.com"]
+  gem.date          = Time.now.strftime("%Y-%m-%d")
+  gem.description   = %q{Handlebars.js source code wrapper for (pre)compilation gems.}
+  gem.summary       = %q{Handlebars.js source code wrapper}
+  gem.homepage      = "https://github.com/handlebars-lang/handlebars.js/"
+  gem.version       = package["version"].sub "-", "."
+  gem.license       = "MIT"
+
+  gem.files = [
+    'handlebars.js',
+    'handlebars.runtime.js',
+    'lib/handlebars/source.rb'
+  ]
+end

components/handlebars.js.nuspec

@@ -0,0 +1,17 @@
+<?xml version="1.0"?>
+<package>
+	<metadata>
+		<id>handlebars.js</id>
+		<version>5.0.0-alpha.1</version>
+		<authors>handlebars.js Authors</authors>
+		<licenseUrl>https://github.com/handlebars-lang/handlebars.js/blob/master/LICENSE</licenseUrl>
+		<projectUrl>https://github.com/handlebars-lang/handlebars.js/</projectUrl>
+		<requireLicenseAcceptance>false</requireLicenseAcceptance>
+		<description>Extension of the Mustache logicless template language</description>
+		<releaseNotes></releaseNotes>
+		<tags>handlebars mustache template html</tags>
+	</metadata>
+	<files>
+		<file src="handlebars.js" target="Content\Scripts" />
+	</files>
+</package>

components/lib/handlebars/source.rb

@@ -0,0 +1,11 @@
+module Handlebars
+  module Source
+    def self.bundled_path
+      File.expand_path("../../../handlebars.js", __FILE__)
+    end
+
+    def self.runtime_bundled_path
+      File.expand_path("../../../handlebars.runtime.js", __FILE__)
+    end
+  end
+end

components/package.json

@@ -0,0 +1,20 @@
+{
+  "name": "handlebars",
+  "version": "5.0.0-alpha.1",
+  "license": "MIT",
+  "jspm": {
+    "main": "handlebars",
+    "shim": {
+      "handlebars": {
+        "exports": "Handlebars"
+      }
+    },
+    "files": [
+      "handlebars.js",
+      "handlebars.runtime.js"
+    ],
+    "buildConfig": {
+      "minify": true
+    }
+  }
+}

dist/handlebars.runtime.js

@@ -1,320 +0,0 @@
-/*
-
-Copyright (C) 2011 by Yehuda Katz
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.
-
-*/
-
-// lib/handlebars/base.js
-
-var Handlebars = {};
-
-(function(Handlebars) {
-
-Handlebars.VERSION = "1.0.0-rc.3";
-Handlebars.COMPILER_REVISION = 2;
-
-Handlebars.REVISION_CHANGES = {
-  1: '<= 1.0.rc.2', // 1.0.rc.2 is actually rev2 but doesn't report it
-  2: '>= 1.0.0-rc.3'
-};
-
-Handlebars.helpers  = {};
-Handlebars.partials = {};
-
-Handlebars.registerHelper = function(name, fn, inverse) {
-  if(inverse) { fn.not = inverse; }
-  this.helpers[name] = fn;
-};
-
-Handlebars.registerPartial = function(name, str) {
-  this.partials[name] = str;
-};
-
-Handlebars.registerHelper('helperMissing', function(arg) {
-  if(arguments.length === 2) {
-    return undefined;
-  } else {
-    throw new Error("Could not find property '" + arg + "'");
-  }
-});
-
-var toString = Object.prototype.toString, functionType = "[object Function]";
-
-Handlebars.registerHelper('blockHelperMissing', function(context, options) {
-  var inverse = options.inverse || function() {}, fn = options.fn;
-
-  var type = toString.call(context);
-
-  if(type === functionType) { context = context.call(this); }
-
-  if(context === true) {
-    return fn(this);
-  } else if(context === false || context == null) {
-    return inverse(this);
-  } else if(type === "[object Array]") {
-    if(context.length > 0) {
-      return Handlebars.helpers.each(context, options);
-    } else {
-      return inverse(this);
-    }
-  } else {
-    return fn(context);
-  }
-});
-
-Handlebars.K = function() {};
-
-Handlebars.createFrame = Object.create || function(object) {
-  Handlebars.K.prototype = object;
-  var obj = new Handlebars.K();
-  Handlebars.K.prototype = null;
-  return obj;
-};
-
-Handlebars.logger = {
-  DEBUG: 0, INFO: 1, WARN: 2, ERROR: 3, level: 3,
-
-  methodMap: {0: 'debug', 1: 'info', 2: 'warn', 3: 'error'},
-
-  // can be overridden in the host environment
-  log: function(level, obj) {
-    if (Handlebars.logger.level <= level) {
-      var method = Handlebars.logger.methodMap[level];
-      if (typeof console !== 'undefined' && console[method]) {
-        console[method].call(console, obj);
-      }
-    }
-  }
-};
-
-Handlebars.log = function(level, obj) { Handlebars.logger.log(level, obj); };
-
-Handlebars.registerHelper('each', function(context, options) {
-  var fn = options.fn, inverse = options.inverse;
-  var i = 0, ret = "", data;
-
-  if (options.data) {
-    data = Handlebars.createFrame(options.data);
-  }
-
-  if(context && typeof context === 'object') {
-    if(context instanceof Array){
-      for(var j = context.length; i<j; i++) {
-        if (data) { data.index = i; }
-        ret = ret + fn(context[i], { data: data });
-      }
-    } else {
-      for(var key in context) {
-        if(context.hasOwnProperty(key)) {
-          if(data) { data.key = key; }
-          ret = ret + fn(context[key], {data: data});
-          i++;
-        }
-      }
-    }
-  }
-
-  if(i === 0){
-    ret = inverse(this);
-  }
-
-  return ret;
-});
-
-Handlebars.registerHelper('if', function(context, options) {
-  var type = toString.call(context);
-  if(type === functionType) { context = context.call(this); }
-
-  if(!context || Handlebars.Utils.isEmpty(context)) {
-    return options.inverse(this);
-  } else {
-    return options.fn(this);
-  }
-});
-
-Handlebars.registerHelper('unless', function(context, options) {
-  var fn = options.fn, inverse = options.inverse;
-  options.fn = inverse;
-  options.inverse = fn;
-
-  return Handlebars.helpers['if'].call(this, context, options);
-});
-
-Handlebars.registerHelper('with', function(context, options) {
-  return options.fn(context);
-});
-
-Handlebars.registerHelper('log', function(context, options) {
-  var level = options.data && options.data.level != null ? parseInt(options.data.level, 10) : 1;
-  Handlebars.log(level, context);
-});
-
-}(Handlebars));
-;
-// lib/handlebars/utils.js
-
-var errorProps = ['description', 'fileName', 'lineNumber', 'message', 'name', 'number', 'stack'];
-
-Handlebars.Exception = function(message) {
-  var tmp = Error.prototype.constructor.apply(this, arguments);
-
-  // Unfortunately errors are not enumerable in Chrome (at least), so `for prop in tmp` doesn't work.
-  for (var idx = 0; idx < errorProps.length; idx++) {
-    this[errorProps[idx]] = tmp[errorProps[idx]];
-  }
-};
-Handlebars.Exception.prototype = new Error();
-
-// Build out our basic SafeString type
-Handlebars.SafeString = function(string) {
-  this.string = string;
-};
-Handlebars.SafeString.prototype.toString = function() {
-  return this.string.toString();
-};
-
-(function() {
-  var escape = {
-    "&": "&amp;",
-    "<": "&lt;",
-    ">": "&gt;",
-    '"': "&quot;",
-    "'": "&#x27;",
-    "`": "&#x60;"
-  };
-
-  var badChars = /[&<>"'`]/g;
-  var possible = /[&<>"'`]/;
-
-  var escapeChar = function(chr) {
-    return escape[chr] || "&amp;";
-  };
-
-  Handlebars.Utils = {
-    escapeExpression: function(string) {
-      // don't escape SafeStrings, since they're already safe
-      if (string instanceof Handlebars.SafeString) {
-        return string.toString();
-      } else if (string == null || string === false) {
-        return "";
-      }
-
-      if(!possible.test(string)) { return string; }
-      return string.replace(badChars, escapeChar);
-    },
-
-    isEmpty: function(value) {
-      if (!value && value !== 0) {
-        return true;
-      } else if(Object.prototype.toString.call(value) === "[object Array]" && value.length === 0) {
-        return true;
-      } else {
-        return false;
-      }
-    }
-  };
-})();
-;
-// lib/handlebars/runtime.js
-
-Handlebars.VM = {
-  template: function(templateSpec) {
-    // Just add water
-    var container = {
-      escapeExpression: Handlebars.Utils.escapeExpression,
-      invokePartial: Handlebars.VM.invokePartial,
-      programs: [],
-      program: function(i, fn, data) {
-        var programWrapper = this.programs[i];
-        if(data) {
-          return Handlebars.VM.program(fn, data);
-        } else if(programWrapper) {
-          return programWrapper;
-        } else {
-          programWrapper = this.programs[i] = Handlebars.VM.program(fn);
-          return programWrapper;
-        }
-      },
-      programWithDepth: Handlebars.VM.programWithDepth,
-      noop: Handlebars.VM.noop,
-      compilerInfo: null
-    };
-
-    return function(context, options) {
-      options = options || {};
-      var result = templateSpec.call(container, Handlebars, context, options.helpers, options.partials, options.data);
-
-      var compilerInfo = container.compilerInfo || [],
-          compilerRevision = compilerInfo[0] || 1,
-          currentRevision = Handlebars.COMPILER_REVISION;
-
-      if (compilerRevision !== currentRevision) {
-        if (compilerRevision < currentRevision) {
-          var runtimeVersions = Handlebars.REVISION_CHANGES[currentRevision],
-              compilerVersions = Handlebars.REVISION_CHANGES[compilerRevision];
-          throw "Template was precompiled with an older version of Handlebars than the current runtime. "+
-                "Please update your precompiler to a newer version ("+runtimeVersions+") or downgrade your runtime to an older version ("+compilerVersions+").";
-        } else {
-          // Use the embedded version info since the runtime doesn't know about this revision yet
-          throw "Template was precompiled with a newer version of Handlebars than the current runtime. "+
-                "Please update your runtime to a newer version ("+compilerInfo[1]+").";
-        }
-      }
-
-      return result;
-    };
-  },
-
-  programWithDepth: function(fn, data, $depth) {
-    var args = Array.prototype.slice.call(arguments, 2);
-
-    return function(context, options) {
-      options = options || {};
-
-      return fn.apply(this, [context, options.data || data].concat(args));
-    };
-  },
-  program: function(fn, data) {
-    return function(context, options) {
-      options = options || {};
-
-      return fn(context, options.data || data);
-    };
-  },
-  noop: function() { return ""; },
-  invokePartial: function(partial, name, context, helpers, partials, data) {
-    var options = { helpers: helpers, partials: partials, data: data };
-
-    if(partial === undefined) {
-      throw new Handlebars.Exception("The partial " + name + " could not be found");
-    } else if(partial instanceof Function) {
-      return partial(context, options);
-    } else if (!Handlebars.compile) {
-      throw new Handlebars.Exception("The partial " + name + " could not be compiled when running in runtime-only mode");
-    } else {
-      partials[name] = Handlebars.compile(partial, {data: data !== undefined});
-      return partials[name](context, options);
-    }
-  }
-};
-
-Handlebars.template = Handlebars.VM.template;
-;

docs/compiler-api.md

@@ -0,0 +1,365 @@
+# Handlebars Compiler APIs
+
+There are a number of formal APIs that tool implementors may interact with.
+
+## AST
+
+Other tools may interact with the formal AST as defined below. Any JSON structure matching this pattern may be used and passed into the `compile` and `precompile` methods in the same way as the text for a template.
+
+AST structures may be generated either with the `Handlebars.parse` method and then manipulated, via the `Handlebars.AST` objects of the same name, or constructed manually as a generic JavaScript object matching the structure defined below.
+
+```javascript
+var ast = Handlebars.parse(myTemplate);
+
+// Modify ast
+
+Handlebars.precompile(ast);
+```
+
+### Parsing
+
+There are two primary APIs that are used to parse an existing template into the AST:
+
+#### parseWithoutProcessing
+
+`Handlebars.parseWithoutProcessing` is the primary mechanism to turn a raw template string into the Handlebars AST described in this document. No processing is done on the resulting AST which makes this ideal for codemod (for source to source transformation) tooling.
+
+Example:
+
+```js
+let ast = Handlebars.parseWithoutProcessing(myTemplate);
+```
+
+#### parse
+
+`Handlebars.parse` will parse the template with `parseWithoutProcessing` (see above) then it will update the AST to strip extraneous whitespace. The whitespace stripping functionality handles two distinct situations:
+
+- Removes whitespace around dynamic statements that are on a line by themselves (aka "stand alone")
+- Applies "whitespace control" characters (i.e. `~`) by truncating the `ContentStatement` `value` property appropriately (e.g. `\n\n{{~foo}}` would have a `ContentStatement` with a `value` of `''`)
+
+`Handlebars.parse` is used internally by `Handlebars.precompile` and `Handlebars.compile`.
+
+Example:
+
+```js
+let ast = Handlebars.parse(myTemplate);
+```
+
+### Basic
+
+```java
+interface Node {
+    type: string;
+    loc: SourceLocation | null;
+}
+
+interface SourceLocation {
+    source: string | null;
+    start: Position;
+    end: Position;
+}
+
+interface Position {
+    line: uint >= 1;
+    column: uint >= 0;
+}
+```
+
+### Programs
+
+```java
+interface Program <: Node {
+    type: "Program";
+    body: [ Statement ];
+
+    blockParams: [ string ];
+}
+```
+
+### Statements
+
+```java
+interface Statement <: Node { }
+
+interface MustacheStatement <: Statement {
+    type: "MustacheStatement";
+
+    path: PathExpression | Literal;
+    params: [ Expression ];
+    hash: Hash;
+
+    escaped: boolean;
+    strip: StripFlags | null;
+}
+
+interface BlockStatement <: Statement {
+    type: "BlockStatement";
+    path: PathExpression | Literal;
+    params: [ Expression ];
+    hash: Hash;
+
+    program: Program | null;
+    inverse: Program | null;
+
+    openStrip: StripFlags | null;
+    inverseStrip: StripFlags | null;
+    closeStrip: StripFlags | null;
+}
+
+interface PartialStatement <: Statement {
+    type: "PartialStatement";
+    name: PathExpression | SubExpression;
+    params: [ Expression ];
+    hash: Hash;
+
+    indent: string;
+    strip: StripFlags | null;
+}
+
+interface PartialBlockStatement <: Statement {
+    type: "PartialBlockStatement";
+    name: PathExpression | SubExpression;
+    params: [ Expression ];
+    hash: Hash;
+
+    program: Program | null;
+
+    indent: string;
+    openStrip: StripFlags | null;
+    closeStrip: StripFlags | null;
+}
+```
+
+`name` will be a `SubExpression` when tied to a dynamic partial, i.e. `{{> (foo) }}`, otherwise this is a path or literal whose `original` value is used to lookup the desired partial.
+
+```java
+interface ContentStatement <: Statement {
+    type: "ContentStatement";
+    value: string;
+    original: string;
+}
+
+interface CommentStatement <: Statement {
+    type: "CommentStatement";
+    value: string;
+
+    strip: StripFlags | null;
+}
+```
+
+```java
+interface Decorator <: Statement {
+    type: "Decorator";
+
+    path: PathExpression | Literal;
+    params: [ Expression ];
+    hash: Hash;
+
+    strip: StripFlags | null;
+}
+
+interface DecoratorBlock <: Statement {
+    type: "DecoratorBlock";
+    path: PathExpression | Literal;
+    params: [ Expression ];
+    hash: Hash;
+
+    program: Program | null;
+
+    openStrip: StripFlags | null;
+    closeStrip: StripFlags | null;
+}
+```
+
+Decorator paths only utilize the `path.original` value and as a consequence do not support depthed evaluation.
+
+### Expressions
+
+```java
+interface Expression <: Node { }
+```
+
+##### SubExpressions
+
+```java
+interface SubExpression <: Expression {
+    type: "SubExpression";
+    path: PathExpression;
+    params: [ Expression ];
+    hash: Hash;
+}
+```
+
+##### Paths
+
+```java
+interface PathExpression <: Expression {
+    type: "PathExpression";
+    data: boolean;
+    depth: uint >= 0;
+    parts: [ string ];
+    original: string;
+}
+```
+
+- `data` is true when the given expression is a `@data` reference.
+- `depth` is an integer representation of which context the expression references. `0` represents the current context, `1` would be `../`, etc.
+- `parts` is an array of the names in the path. `foo.bar` would be `['foo', 'bar']`. Scope references, `.`, `..`, and `this` should be omitted from this array.
+- `original` is the path as entered by the user. Separator and scope references are left untouched.
+
+##### Literals
+
+```java
+interface Literal <: Expression { }
+
+interface StringLiteral <: Literal {
+    type: "StringLiteral";
+    value: string;
+    original: string;
+}
+
+interface BooleanLiteral <: Literal {
+    type: "BooleanLiteral";
+    value: boolean;
+    original: boolean;
+}
+
+interface NumberLiteral <: Literal {
+    type: "NumberLiteral";
+    value: number;
+    original: number;
+}
+
+interface UndefinedLiteral <: Literal {
+    type: "UndefinedLiteral";
+}
+
+interface NullLiteral <: Literal {
+    type: "NullLiteral";
+}
+```
+
+### Miscellaneous
+
+```java
+interface Hash <: Node {
+    type: "Hash";
+    pairs: [ HashPair ];
+}
+
+interface HashPair <: Node {
+    type: "HashPair";
+    key: string;
+    value: Expression;
+}
+
+interface StripFlags {
+    open: boolean;
+    close: boolean;
+}
+```
+
+`StripFlags` are used to signify whitespace control character that may have been entered on a given statement.
+
+## AST Visitor
+
+`Handlebars.Visitor` is available as a base class for general interaction with AST structures. This will by default traverse the entire tree and individual methods may be overridden to provide specific responses to particular nodes.
+
+Recording all referenced partial names:
+
+```javascript
+var Visitor = Handlebars.Visitor;
+
+function ImportScanner() {
+  this.partials = [];
+}
+ImportScanner.prototype = new Visitor();
+
+ImportScanner.prototype.PartialStatement = function (partial) {
+  this.partials.push({ request: partial.name.original });
+
+  Visitor.prototype.PartialStatement.call(this, partial);
+};
+
+var scanner = new ImportScanner();
+scanner.accept(ast);
+```
+
+The current node's ancestors will be maintained in the `parents` array, with the most recent parent listed first.
+
+The visitor may also be configured to operate in mutation mode by setting the `mutating` field to true. When in this mode, handler methods may return any valid AST node and it will replace the one they are currently operating on. Returning `false` will remove the given value (if valid) and returning `undefined` will leave the node intact. This return structure only apply to mutation mode and non-mutation mode visitors are free to return whatever values they wish.
+
+Implementors that may need to support mutation mode are encouraged to utilize the `acceptKey`, `acceptRequired` and `acceptArray` helpers which provide the conditional overwrite behavior as well as implement sanity checks where pertinent.
+
+## JavaScript Compiler
+
+The `Handlebars.JavaScriptCompiler` object has a number of methods that may be customized to alter the output of the compiler:
+
+- `nameLookup(parent, name, type)`
+  Used to generate the code to resolve a given path component.
+  - `parent` is the existing code in the path resolution
+  - `name` is the current path component
+  - `type` is the type of name being evaluated. May be one of `context`, `data`, `helper`, `decorator`, or `partial`.
+
+  Note that this does not impact dynamic partials, which implementors need to be aware of. Overriding `VM.resolvePartial` may be required to support dynamic cases.
+
+- `depthedLookup(name)`
+  Used to generate code that resolves parameters within any context in the stack. Is only used in `compat` mode.
+
+- `compilerInfo()`
+  Allows for custom compiler flags used in the runtime version checking logic.
+
+- `appendToBuffer(source, location, explicit)`
+  Allows for code buffer emitting code. Defaults behavior is string concatenation.
+  - `source` is the source code whose result is to be appending
+  - `location` is the location of the source in the source map.
+  - `explicit` is a flag signaling that the emit operation must occur, vs. the lazy evaled options otherwise.
+
+- `initializeBuffer()`
+  Allows for buffers other than the default string buffer to be used. Generally needs to be paired with a custom `appendToBuffer` implementation.
+
+### Example for the compiler api.
+
+This example changes all lookups of properties are performed by a helper (`lookupLowerCase`) which looks for `test` if `{{Test}}` occurs in the template. This is just to illustrate how compiler behavior can be change.
+
+There is also [a jsfiddle with this code](https://jsfiddle.net/9D88g/162/) if you want to play around with it.
+
+```javascript
+function MyCompiler() {
+  Handlebars.JavaScriptCompiler.apply(this, arguments);
+}
+MyCompiler.prototype = new Handlebars.JavaScriptCompiler();
+
+// Use this compile to compile BlockStatment-Blocks
+MyCompiler.prototype.compiler = MyCompiler;
+
+MyCompiler.prototype.nameLookup = function (parent, name, type) {
+  if (type === 'context') {
+    return this.source.functionCall('helpers.lookupLowerCase', '', [
+      parent,
+      JSON.stringify(name),
+    ]);
+  } else {
+    return Handlebars.JavaScriptCompiler.prototype.nameLookup.call(
+      this,
+      parent,
+      name,
+      type
+    );
+  }
+};
+
+var env = Handlebars.create();
+env.registerHelper('lookupLowerCase', function (parent, name) {
+  return parent[name.toLowerCase()];
+});
+
+env.JavaScriptCompiler = MyCompiler;
+
+var template = env.compile('{{#each Test}} ({{Value}}) {{/each}}');
+console.log(
+  template({
+    test: [{ value: 'a' }, { value: 'b' }, { value: 'c' }],
+  })
+);
+```

docs/decorators-api.md

@@ -0,0 +1,21 @@
+# Decorators
+
+**Decorators are deprecated, please join the discussion at [#1574](https://github.com/handlebars-lang/handlebars.js/issues/1574) to see what we can do about it.**
+
+Decorators allow for blocks to be annotated with metadata or wrapped in functionality prior to execution of the block. This may be used to communicate with the containing helper or to set up a particular state in the system prior to running the block.
+
+Decorators are registered through similar methods as helpers, `registerDecorators` and `unregisterDecorators`. These can then be referenced via the friendly name in the template using the `{{* decorator}}` and `{{#* decorator}}{/decorator}}` syntaxes. These syntaxes are derivatives of the normal mustache syntax and as such have all of the same argument and whitespace behaviors.
+
+Decorators are executed when the block program is instantiated and are passed `(program, props, container, context, data, blockParams, depths)`.
+
+- `program`: The block to wrap
+- `props`: Object used to set metadata on the final function. Any values set on this object will be set on the function, regardless of if the original function is replaced or not. Metadata should be applied using this object as values applied to `program` may be masked by subsequent decorators that may wrap `program`.
+- `container`: The current runtime container
+- `context`: The current context. Since the decorator is run before the block that contains it, this is the parent context.
+- `data`: The current `@data` values
+- `blockParams`: The current block parameters stack
+- `depths`: The current context stack
+
+Decorators may set values on `props` or return a modified function that wraps `program` in particular behaviors. If the decorator returns nothing, then `program` is left unaltered.
+
+The [inline partial](https://github.com/handlebars-lang/handlebars.js/blob/master/lib/handlebars/decorators/inline.js) implementation provides an example of decorators being used for both metadata and wrapping behaviors.

eslint.config.mjs

@@ -0,0 +1,17 @@
+import compat from 'eslint-plugin-compat';
+
+export default [
+  {
+    // Ignore everything except lib/
+    ignores: ['**', '!lib/**'],
+  },
+  {
+    // Only check browser API compat in the runtime library code.
+    // All other linting is handled by oxlint.
+    ...compat.configs['flat/recommended'],
+    files: ['lib/**/*.js'],
+    linterOptions: {
+      reportUnusedDisableDirectives: 'off',
+    },
+  },
+];

lib/handlebars.js

@@ -1,32 +1,47 @@
-var handlebars = require("./handlebars/base"),
+import {
+  parser as Parser,
+  parse,
+  parseWithoutProcessing,
+  Visitor,
+} from '@handlebars/parser';
 
-// Each of these augment the Handlebars object. No need to setup here.
-// (This is done to easily share code between commonjs and browse envs)
-  utils = require("./handlebars/utils"),
-  compiler = require("./handlebars/compiler"),
-  runtime = require("./handlebars/runtime");
+import runtime from './handlebars.runtime';
 
-var create = function() {
-  var hb = handlebars.create();
+// Compiler imports
+import AST from './handlebars/compiler/ast';
+import { Compiler, compile, precompile } from './handlebars/compiler/compiler';
+import JavaScriptCompiler from './handlebars/compiler/javascript-compiler';
 
-  utils.attach(hb);
-  compiler.attach(hb);
-  runtime.attach(hb);
+import noConflict from './handlebars/no-conflict';
+
+let _create = runtime.create;
+function create() {
+  let hb = _create();
+
+  hb.compile = function (input, options) {
+    return compile(input, options, hb);
+  };
+  hb.precompile = function (input, options) {
+    return precompile(input, options, hb);
+  };
+
+  hb.AST = AST;
+  hb.Compiler = Compiler;
+  hb.JavaScriptCompiler = JavaScriptCompiler;
+  hb.Parser = Parser;
+  hb.parse = parse;
+  hb.parseWithoutProcessing = parseWithoutProcessing;
 
   return hb;
-};
+}
 
-var Handlebars = create();
-Handlebars.create = create;
+let inst = create();
+inst.create = create;
 
-module.exports = Handlebars; // instantiate an instance
+noConflict(inst);
 
-// BEGIN(BROWSER)
+inst.Visitor = Visitor;
 
-// END(BROWSER)
+inst['default'] = inst;
 
-// USAGE:
-// var handlebars = require('handlebars');
-
-// var singleton = handlebars.Handlebars,
-//  local = handlebars.create();
+export default inst;

lib/handlebars.runtime.js

@@ -0,0 +1,40 @@
+import { Exception } from '@handlebars/parser';
+import * as base from './handlebars/base';
+
+// Each of these augment the Handlebars object. No need to setup here.
+// (This is done to easily share code between commonjs and browse envs)
+import SafeString from './handlebars/safe-string';
+import * as Utils from './handlebars/utils';
+import * as runtime from './handlebars/runtime';
+
+import noConflict from './handlebars/no-conflict';
+
+// For compatibility and usage outside of module systems, make the Handlebars object a namespace
+function create() {
+  let hb = new base.HandlebarsEnvironment();
+
+  Utils.extend(hb, base);
+  hb.SafeString = SafeString;
+  hb.Exception = Exception;
+  hb.Utils = Utils;
+  hb.escapeExpression = Utils.escapeExpression;
+
+  // Spread into a plain object so that runtime functions (e.g. checkRevision)
+  // can be overridden by consumers. ES module namespace objects are sealed with
+  // getter-only properties per spec, which would prevent monkey-patching.
+  hb.VM = { ...runtime };
+  hb.template = function (spec) {
+    return runtime.template(spec, hb);
+  };
+
+  return hb;
+}
+
+let inst = create();
+inst.create = create;
+
+noConflict(inst);
+
+inst['default'] = inst;
+
+export default inst;

lib/handlebars/base.js

@@ -1,155 +1,94 @@
-/*jshint eqnull: true */
+import { Exception } from '@handlebars/parser';
+import { createFrame, extend, toString } from './utils';
+import { registerDefaultHelpers } from './helpers';
+import { registerDefaultDecorators } from './decorators';
+import logger from './logger';
+import { resetLoggedProperties } from './internal/proto-access';
 
-module.exports.create = function() {
+export const VERSION = '4.7.7';
+export const COMPILER_REVISION = 8;
+export const LAST_COMPATIBLE_COMPILER_REVISION = 7;
 
-// BEGIN(BROWSER)
-
-var Handlebars = {};
-
-(function(Handlebars) {
-
-Handlebars.VERSION = "1.0.0-rc.3";
-Handlebars.COMPILER_REVISION = 2;
-
-Handlebars.REVISION_CHANGES = {
+export const REVISION_CHANGES = {
   1: '<= 1.0.rc.2', // 1.0.rc.2 is actually rev2 but doesn't report it
-  2: '>= 1.0.0-rc.3'
+  2: '== 1.0.0-rc.3',
+  3: '== 1.0.0-rc.4',
+  4: '== 1.x.x',
+  5: '== 2.0.0-alpha.x',
+  6: '>= 2.0.0-beta.1',
+  7: '>= 4.0.0 <4.3.0',
+  8: '>= 4.3.0',
 };
 
-Handlebars.helpers  = {};
-Handlebars.partials = {};
+const objectType = '[object Object]';
 
-Handlebars.registerHelper = function(name, fn, inverse) {
-  if(inverse) { fn.not = inverse; }
-  this.helpers[name] = fn;
-};
+export function HandlebarsEnvironment(helpers, partials, decorators) {
+  this.helpers = helpers || {};
+  this.partials = partials || {};
+  this.decorators = decorators || {};
 
-Handlebars.registerPartial = function(name, str) {
-  this.partials[name] = str;
-};
+  registerDefaultHelpers(this);
+  registerDefaultDecorators(this);
+}
 
-Handlebars.registerHelper('helperMissing', function(arg) {
-  if(arguments.length === 2) {
-    return undefined;
-  } else {
-    throw new Error("Could not find property '" + arg + "'");
-  }
-});
+HandlebarsEnvironment.prototype = {
+  constructor: HandlebarsEnvironment,
 
-var toString = Object.prototype.toString, functionType = "[object Function]";
+  logger: logger,
+  log: logger.log,
 
-Handlebars.registerHelper('blockHelperMissing', function(context, options) {
-  var inverse = options.inverse || function() {}, fn = options.fn;
-
-  var type = toString.call(context);
-
-  if(type === functionType) { context = context.call(this); }
-
-  if(context === true) {
-    return fn(this);
-  } else if(context === false || context == null) {
-    return inverse(this);
-  } else if(type === "[object Array]") {
-    if(context.length > 0) {
-      return Handlebars.helpers.each(context, options);
+  registerHelper: function (name, fn) {
+    if (toString.call(name) === objectType) {
+      if (fn) {
+        throw new Exception('Arg not supported with multiple helpers');
+      }
+      extend(this.helpers, name);
     } else {
-      return inverse(this);
+      this.helpers[name] = fn;
     }
-  } else {
-    return fn(context);
-  }
-});
+  },
+  unregisterHelper: function (name) {
+    delete this.helpers[name];
+  },
 
-Handlebars.K = function() {};
-
-Handlebars.createFrame = Object.create || function(object) {
-  Handlebars.K.prototype = object;
-  var obj = new Handlebars.K();
-  Handlebars.K.prototype = null;
-  return obj;
-};
-
-Handlebars.logger = {
-  DEBUG: 0, INFO: 1, WARN: 2, ERROR: 3, level: 3,
-
-  methodMap: {0: 'debug', 1: 'info', 2: 'warn', 3: 'error'},
-
-  // can be overridden in the host environment
-  log: function(level, obj) {
-    if (Handlebars.logger.level <= level) {
-      var method = Handlebars.logger.methodMap[level];
-      if (typeof console !== 'undefined' && console[method]) {
-        console[method].call(console, obj);
-      }
-    }
-  }
-};
-
-Handlebars.log = function(level, obj) { Handlebars.logger.log(level, obj); };
-
-Handlebars.registerHelper('each', function(context, options) {
-  var fn = options.fn, inverse = options.inverse;
-  var i = 0, ret = "", data;
-
-  if (options.data) {
-    data = Handlebars.createFrame(options.data);
-  }
-
-  if(context && typeof context === 'object') {
-    if(context instanceof Array){
-      for(var j = context.length; i<j; i++) {
-        if (data) { data.index = i; }
-        ret = ret + fn(context[i], { data: data });
-      }
+  registerPartial: function (name, partial) {
+    if (toString.call(name) === objectType) {
+      extend(this.partials, name);
     } else {
-      for(var key in context) {
-        if(context.hasOwnProperty(key)) {
-          if(data) { data.key = key; }
-          ret = ret + fn(context[key], {data: data});
-          i++;
-        }
+      if (typeof partial === 'undefined') {
+        throw new Exception(
+          `Attempting to register a partial called "${name}" as undefined`
+        );
       }
+      this.partials[name] = partial;
     }
-  }
+  },
+  unregisterPartial: function (name) {
+    delete this.partials[name];
+  },
 
-  if(i === 0){
-    ret = inverse(this);
-  }
-
-  return ret;
-});
-
-Handlebars.registerHelper('if', function(context, options) {
-  var type = toString.call(context);
-  if(type === functionType) { context = context.call(this); }
-
-  if(!context || Handlebars.Utils.isEmpty(context)) {
-    return options.inverse(this);
-  } else {
-    return options.fn(this);
-  }
-});
-
-Handlebars.registerHelper('unless', function(context, options) {
-  var fn = options.fn, inverse = options.inverse;
-  options.fn = inverse;
-  options.inverse = fn;
-
-  return Handlebars.helpers['if'].call(this, context, options);
-});
-
-Handlebars.registerHelper('with', function(context, options) {
-  return options.fn(context);
-});
-
-Handlebars.registerHelper('log', function(context, options) {
-  var level = options.data && options.data.level != null ? parseInt(options.data.level, 10) : 1;
-  Handlebars.log(level, context);
-});
-
-}(Handlebars));
-
-// END(BROWSER)
-
-return Handlebars;
+  registerDecorator: function (name, fn) {
+    if (toString.call(name) === objectType) {
+      if (fn) {
+        throw new Exception('Arg not supported with multiple decorators');
+      }
+      extend(this.decorators, name);
+    } else {
+      this.decorators[name] = fn;
+    }
+  },
+  unregisterDecorator: function (name) {
+    delete this.decorators[name];
+  },
+  /**
+   * Reset the memory of illegal property accesses that have already been logged.
+   * @deprecated should only be used in handlebars test-cases
+   */
+  resetLoggedPropertyAccesses() {
+    resetLoggedProperties();
+  },
 };
+
+export let log = logger.log;
+
+export { createFrame, logger };

lib/handlebars/compiler/ast.js

@@ -1,136 +1,32 @@
-exports.attach = function(Handlebars) {
-
-// BEGIN(BROWSER)
-(function() {
-
-  Handlebars.AST = {};
-
-  Handlebars.AST.ProgramNode = function(statements, inverse) {
-    this.type = "program";
-    this.statements = statements;
-    if(inverse) { this.inverse = new Handlebars.AST.ProgramNode(inverse); }
-  };
-
-  Handlebars.AST.MustacheNode = function(rawParams, hash, unescaped) {
-    this.type = "mustache";
-    this.escaped = !unescaped;
-    this.hash = hash;
-
-    var id = this.id = rawParams[0];
-    var params = this.params = rawParams.slice(1);
-
-    // a mustache is an eligible helper if:
-    // * its id is simple (a single part, not `this` or `..`)
-    var eligibleHelper = this.eligibleHelper = id.isSimple;
-
+let AST = {
+  // Public API used to evaluate derived attributes regarding AST nodes
+  helpers: {
     // a mustache is definitely a helper if:
     // * it is an eligible helper, and
     // * it has at least one parameter or hash segment
-    this.isHelper = eligibleHelper && (params.length || hash);
+    helperExpression: function (node) {
+      return (
+        node.type === 'SubExpression' ||
+        ((node.type === 'MustacheStatement' ||
+          node.type === 'BlockStatement') &&
+          !!((node.params && node.params.length) || node.hash))
+      );
+    },
 
-    // if a mustache is an eligible helper but not a definite
-    // helper, it is ambiguous, and will be resolved in a later
-    // pass or at runtime.
-  };
-
-  Handlebars.AST.PartialNode = function(partialName, context) {
-    this.type         = "partial";
-    this.partialName  = partialName;
-    this.context      = context;
-  };
-
-  Handlebars.AST.BlockNode = function(mustache, program, inverse, close) {
-    var verifyMatch = function(open, close) {
-      if(open.original !== close.original) {
-        throw new Handlebars.Exception(open.original + " doesn't match " + close.original);
-      }
-    };
-
-    verifyMatch(mustache.id, close);
-    this.type = "block";
-    this.mustache = mustache;
-    this.program  = program;
-    this.inverse  = inverse;
-
-    if (this.inverse && !this.program) {
-      this.isInverse = true;
-    }
-  };
-
-  Handlebars.AST.ContentNode = function(string) {
-    this.type = "content";
-    this.string = string;
-  };
-
-  Handlebars.AST.HashNode = function(pairs) {
-    this.type = "hash";
-    this.pairs = pairs;
-  };
-
-  Handlebars.AST.IdNode = function(parts) {
-    this.type = "ID";
-    this.original = parts.join(".");
-
-    var dig = [], depth = 0;
-
-    for(var i=0,l=parts.length; i<l; i++) {
-      var part = parts[i];
-
-      if (part === ".." || part === "." || part === "this") {
-        if (dig.length > 0) { throw new Handlebars.Exception("Invalid path: " + this.original); }
-        else if (part === "..") { depth++; }
-        else { this.isScoped = true; }
-      }
-      else { dig.push(part); }
-    }
-
-    this.parts    = dig;
-    this.string   = dig.join('.');
-    this.depth    = depth;
+    scopedId: function (path) {
+      return /^\.|this\b/.test(path.original);
+    },
 
     // an ID is simple if it only has one part, and that part is not
     // `..` or `this`.
-    this.isSimple = parts.length === 1 && !this.isScoped && depth === 0;
-
-    this.stringModeValue = this.string;
-  };
-
-  Handlebars.AST.PartialNameNode = function(name) {
-    this.type = "PARTIAL_NAME";
-    this.name = name;
-  };
-
-  Handlebars.AST.DataNode = function(id) {
-    this.type = "DATA";
-    this.id = id;
-  };
-
-  Handlebars.AST.StringNode = function(string) {
-    this.type = "STRING";
-    this.string = string;
-    this.stringModeValue = string;
-  };
-
-  Handlebars.AST.IntegerNode = function(integer) {
-    this.type = "INTEGER";
-    this.integer = integer;
-    this.stringModeValue = Number(integer);
-  };
-
-  Handlebars.AST.BooleanNode = function(bool) {
-    this.type = "BOOLEAN";
-    this.bool = bool;
-    this.stringModeValue = bool === "true";
-  };
-
-  Handlebars.AST.CommentNode = function(comment) {
-    this.type = "comment";
-    this.comment = comment;
-  };
-
-})();
-// END(BROWSER)
-
-return Handlebars;
+    simpleId: function (path) {
+      return (
+        path.parts.length === 1 && !AST.helpers.scopedId(path) && !path.depth
+      );
+    },
+  },
 };
 
+// Must be exported as an object rather than the root of the module as the jison lexer
+// must modify the object to operate properly.
+export default AST;

lib/handlebars/compiler/base.js

@@ -1,24 +0,0 @@
-var handlebars = require("./parser");
-
-exports.attach = function(Handlebars) {
-
-// BEGIN(BROWSER)
-
-Handlebars.Parser = handlebars;
-
-Handlebars.parse = function(input) {
-
-  // Just return if an already-compile AST was passed in.
-  if(input.constructor === Handlebars.AST.ProgramNode) { return input; }
-
-  Handlebars.Parser.yy = Handlebars.AST;
-  return Handlebars.Parser.parse(input);
-};
-
-Handlebars.print = function(ast) {
-  return new Handlebars.PrintVisitor().accept(ast);
-};
-// END(BROWSER)
-
-return Handlebars;
-};

lib/handlebars/compiler/code-gen.js

@@ -0,0 +1,177 @@
+/* global define */
+import { isArray } from '../utils';
+
+let SourceNode;
+
+try {
+  /* v8 ignore next */
+  if (typeof define !== 'function' || !define.amd) {
+    // We don't support this in AMD environments. For these environments, we assume that
+    // they are running on the browser and thus have no need for the source-map library.
+    // The variable indirection prevents bundlers from statically resolving and bundling
+    // source-map (which requires Node-built-ins). The stub SourceNode below handles
+    // browser/bundled usage. Bundlers may emit a "Critical dependency" warning — this
+    // is expected and harmless.
+    let mod = 'source-map';
+    let SourceMap = require(mod);
+    SourceNode = SourceMap.SourceNode;
+  }
+  // oxlint-disable-next-line no-unused-vars -- Babel 5 requires named catch param
+} catch (err) {
+  /* NOP */
+}
+
+/* v8 ignore next -- tested but not covered due to dist build */
+if (!SourceNode) {
+  SourceNode = function (line, column, srcFile, chunks) {
+    this.src = '';
+    if (chunks) {
+      this.add(chunks);
+    }
+  };
+  /* v8 ignore next */
+  SourceNode.prototype = {
+    add: function (chunks) {
+      if (isArray(chunks)) {
+        chunks = chunks.join('');
+      }
+      this.src += chunks;
+    },
+    prepend: function (chunks) {
+      if (isArray(chunks)) {
+        chunks = chunks.join('');
+      }
+      this.src = chunks + this.src;
+    },
+    toStringWithSourceMap: function () {
+      return { code: this.toString() };
+    },
+    toString: function () {
+      return this.src;
+    },
+  };
+}
+
+function castChunk(chunk, codeGen, loc) {
+  if (isArray(chunk)) {
+    let ret = [];
+
+    for (let i = 0, len = chunk.length; i < len; i++) {
+      ret.push(codeGen.wrap(chunk[i], loc));
+    }
+    return ret;
+  } else if (typeof chunk === 'boolean' || typeof chunk === 'number') {
+    // Handle primitives that the SourceNode will throw up on
+    return chunk + '';
+  }
+  return chunk;
+}
+
+function CodeGen(srcFile) {
+  this.srcFile = srcFile;
+  this.source = [];
+}
+
+CodeGen.prototype = {
+  isEmpty() {
+    return !this.source.length;
+  },
+  prepend: function (source, loc) {
+    this.source.unshift(this.wrap(source, loc));
+  },
+  push: function (source, loc) {
+    this.source.push(this.wrap(source, loc));
+  },
+
+  merge: function () {
+    let source = this.empty();
+    this.each(function (line) {
+      source.add(['  ', line, '\n']);
+    });
+    return source;
+  },
+
+  each: function (iter) {
+    for (let i = 0, len = this.source.length; i < len; i++) {
+      iter(this.source[i]);
+    }
+  },
+
+  empty: function () {
+    let loc = this.currentLocation || { start: {} };
+    return new SourceNode(loc.start.line, loc.start.column, this.srcFile);
+  },
+  wrap: function (chunk, loc = this.currentLocation || { start: {} }) {
+    if (chunk instanceof SourceNode) {
+      return chunk;
+    }
+
+    chunk = castChunk(chunk, this, loc);
+
+    return new SourceNode(
+      loc.start.line,
+      loc.start.column,
+      this.srcFile,
+      chunk
+    );
+  },
+
+  functionCall: function (fn, type, params) {
+    params = this.generateList(params);
+    return this.wrap([fn, type ? '.' + type + '(' : '(', params, ')']);
+  },
+
+  quotedString: function (str) {
+    return (
+      '"' +
+      (str + '')
+        .replace(/\\/g, '\\\\')
+        .replace(/"/g, '\\"')
+        .replace(/\n/g, '\\n')
+        .replace(/\r/g, '\\r')
+        .replace(/\u2028/g, '\\u2028') // Per Ecma-262 7.3 + 7.8.4
+        .replace(/\u2029/g, '\\u2029') +
+      '"'
+    );
+  },
+
+  objectLiteral: function (obj) {
+    let pairs = [];
+
+    Object.keys(obj).forEach((key) => {
+      let value = castChunk(obj[key], this);
+      if (value !== 'undefined') {
+        pairs.push([this.quotedString(key), ':', value]);
+      }
+    });
+
+    let ret = this.generateList(pairs);
+    ret.prepend('{');
+    ret.add('}');
+    return ret;
+  },
+
+  generateList: function (entries) {
+    let ret = this.empty();
+
+    for (let i = 0, len = entries.length; i < len; i++) {
+      if (i) {
+        ret.add(',');
+      }
+
+      ret.add(castChunk(entries[i], this));
+    }
+
+    return ret;
+  },
+
+  generateArray: function (entries) {
+    let ret = this.generateList(entries);
+    ret.prepend('[');
+    ret.add(']');
+
+    return ret;
+  },
+};
+
+export default CodeGen;

lib/handlebars/compiler/index.js

@@ -1,16 +0,0 @@
-// Each of these module will augment the Handlebars object as it loads. No need to perform addition operations
-module.exports.attach = function(Handlebars) {
-
-var visitor = require("./visitor"),
-    printer = require("./printer"),
-    ast = require("./ast"),
-    compiler = require("./compiler");
-
-visitor.attach(Handlebars);
-printer.attach(Handlebars);
-ast.attach(Handlebars);
-compiler.attach(Handlebars);
-
-return Handlebars;
-
-};

lib/handlebars/compiler/printer.js

@@ -1,134 +0,0 @@
-exports.attach = function(Handlebars) {
-
-// BEGIN(BROWSER)
-
-Handlebars.PrintVisitor = function() { this.padding = 0; };
-Handlebars.PrintVisitor.prototype = new Handlebars.Visitor();
-
-Handlebars.PrintVisitor.prototype.pad = function(string, newline) {
-  var out = "";
-
-  for(var i=0,l=this.padding; i<l; i++) {
-    out = out + "  ";
-  }
-
-  out = out + string;
-
-  if(newline !== false) { out = out + "\n"; }
-  return out;
-};
-
-Handlebars.PrintVisitor.prototype.program = function(program) {
-  var out = "",
-      statements = program.statements,
-      inverse = program.inverse,
-      i, l;
-
-  for(i=0, l=statements.length; i<l; i++) {
-    out = out + this.accept(statements[i]);
-  }
-
-  this.padding--;
-
-  return out;
-};
-
-Handlebars.PrintVisitor.prototype.block = function(block) {
-  var out = "";
-
-  out = out + this.pad("BLOCK:");
-  this.padding++;
-  out = out + this.accept(block.mustache);
-  if (block.program) {
-    out = out + this.pad("PROGRAM:");
-    this.padding++;
-    out = out + this.accept(block.program);
-    this.padding--;
-  }
-  if (block.inverse) {
-    if (block.program) { this.padding++; }
-    out = out + this.pad("{{^}}");
-    this.padding++;
-    out = out + this.accept(block.inverse);
-    this.padding--;
-    if (block.program) { this.padding--; }
-  }
-  this.padding--;
-
-  return out;
-};
-
-Handlebars.PrintVisitor.prototype.mustache = function(mustache) {
-  var params = mustache.params, paramStrings = [], hash;
-
-  for(var i=0, l=params.length; i<l; i++) {
-    paramStrings.push(this.accept(params[i]));
-  }
-
-  params = "[" + paramStrings.join(", ") + "]";
-
-  hash = mustache.hash ? " " + this.accept(mustache.hash) : "";
-
-  return this.pad("{{ " + this.accept(mustache.id) + " " + params + hash + " }}");
-};
-
-Handlebars.PrintVisitor.prototype.partial = function(partial) {
-  var content = this.accept(partial.partialName);
-  if(partial.context) { content = content + " " + this.accept(partial.context); }
-  return this.pad("{{> " + content + " }}");
-};
-
-Handlebars.PrintVisitor.prototype.hash = function(hash) {
-  var pairs = hash.pairs;
-  var joinedPairs = [], left, right;
-
-  for(var i=0, l=pairs.length; i<l; i++) {
-    left = pairs[i][0];
-    right = this.accept(pairs[i][1]);
-    joinedPairs.push( left + "=" + right );
-  }
-
-  return "HASH{" + joinedPairs.join(", ") + "}";
-};
-
-Handlebars.PrintVisitor.prototype.STRING = function(string) {
-  return '"' + string.string + '"';
-};
-
-Handlebars.PrintVisitor.prototype.INTEGER = function(integer) {
-  return "INTEGER{" + integer.integer + "}";
-};
-
-Handlebars.PrintVisitor.prototype.BOOLEAN = function(bool) {
-  return "BOOLEAN{" + bool.bool + "}";
-};
-
-Handlebars.PrintVisitor.prototype.ID = function(id) {
-  var path = id.parts.join("/");
-  if(id.parts.length > 1) {
-    return "PATH:" + path;
-  } else {
-    return "ID:" + path;
-  }
-};
-
-Handlebars.PrintVisitor.prototype.PARTIAL_NAME = function(partialName) {
-    return "PARTIAL:" + partialName.name;
-};
-
-Handlebars.PrintVisitor.prototype.DATA = function(data) {
-  return "@" + data.id;
-};
-
-Handlebars.PrintVisitor.prototype.content = function(content) {
-  return this.pad("CONTENT[ '" + content.string + "' ]");
-};
-
-Handlebars.PrintVisitor.prototype.comment = function(comment) {
-  return this.pad("{{! '" + comment.comment + "' }}");
-};
-// END(BROWSER)
-
-return Handlebars;
-};
-

lib/handlebars/compiler/visitor.js

@@ -1,18 +0,0 @@
-exports.attach = function(Handlebars) {
-
-// BEGIN(BROWSER)
-
-Handlebars.Visitor = function() {};
-
-Handlebars.Visitor.prototype = {
-  accept: function(object) {
-    return this[object.type](object);
-  }
-};
-
-// END(BROWSER)
-
-return Handlebars;
-};
-
-

lib/handlebars/decorators.js

@@ -0,0 +1,5 @@
+import registerInline from './decorators/inline';
+
+export function registerDefaultDecorators(instance) {
+  registerInline(instance);
+}

lib/handlebars/decorators/inline.js

@@ -0,0 +1,25 @@
+import { extend } from '../utils';
+
+export default function (instance) {
+  instance.registerDecorator(
+    'inline',
+    function (fn, props, container, options) {
+      let ret = fn;
+      if (!props.partials) {
+        props.partials = {};
+        ret = function (context, options) {
+          // Create a new partials stack frame prior to exec.
+          let original = container.partials;
+          container.partials = extend({}, original, props.partials);
+          let ret = fn(context, options);
+          container.partials = original;
+          return ret;
+        };
+      }
+
+      props.partials[options.args[0]] = options.fn;
+
+      return ret;
+    }
+  );
+}

lib/handlebars/helpers.js

@@ -0,0 +1,27 @@
+import registerBlockHelperMissing from './helpers/block-helper-missing';
+import registerEach from './helpers/each';
+import registerHelperMissing from './helpers/helper-missing';
+import registerIf from './helpers/if';
+import registerLog from './helpers/log';
+import registerLookup from './helpers/lookup';
+import registerWith from './helpers/with';
+
+export function registerDefaultHelpers(instance) {
+  registerBlockHelperMissing(instance);
+  registerEach(instance);
+  registerHelperMissing(instance);
+  registerIf(instance);
+  registerLog(instance);
+  registerLookup(instance);
+  registerWith(instance);
+}
+
+export function moveHelperToHooks(instance, helperName, keepHelper) {
+  if (instance.helpers[helperName]) {
+    instance.hooks[helperName] = instance.helpers[helperName];
+    if (!keepHelper) {
+      // Using delete is slow
+      instance.helpers[helperName] = undefined;
+    }
+  }
+}

lib/handlebars/helpers/block-helper-missing.js

@@ -0,0 +1,22 @@
+import { isArray } from '../utils';
+
+export default function (instance) {
+  instance.registerHelper('blockHelperMissing', function (context, options) {
+    let inverse = options.inverse,
+      fn = options.fn;
+
+    if (context === true) {
+      return fn(this);
+    } else if (context === false || context == null) {
+      return inverse(this);
+    } else if (isArray(context)) {
+      if (context.length > 0) {
+        return instance.helpers.each(context, options);
+      } else {
+        return inverse(this);
+      }
+    } else {
+      return fn(context, options);
+    }
+  });
+}

lib/handlebars/helpers/each.js

@@ -0,0 +1,92 @@
+import { Exception } from '@handlebars/parser';
+import { createFrame, isArray, isFunction, isMap, isSet } from '../utils';
+
+export default function (instance) {
+  instance.registerHelper('each', function (context, options) {
+    if (!options) {
+      throw new Exception('Must pass iterator to #each');
+    }
+
+    let fn = options.fn,
+      inverse = options.inverse,
+      i = 0,
+      ret = '',
+      data;
+
+    if (isFunction(context)) {
+      context = context.call(this);
+    }
+
+    if (options.data) {
+      data = createFrame(options.data);
+    }
+
+    function execIteration(field, value, index, last) {
+      if (data) {
+        data.key = field;
+        data.index = index;
+        data.first = index === 0;
+        data.last = !!last;
+      }
+
+      ret =
+        ret +
+        fn(value, {
+          data: data,
+          blockParams: [context[field], field],
+        });
+    }
+
+    if (context && typeof context === 'object') {
+      if (isArray(context)) {
+        for (let j = context.length; i < j; i++) {
+          if (i in context) {
+            execIteration(i, context[i], i, i === context.length - 1);
+          }
+        }
+      } else if (isMap(context)) {
+        const j = context.size;
+        for (const [key, value] of context) {
+          execIteration(key, value, i++, i === j);
+        }
+      } else if (isSet(context)) {
+        const j = context.size;
+        for (const value of context) {
+          execIteration(i, value, i++, i === j);
+        }
+      } else if (typeof Symbol === 'function' && context[Symbol.iterator]) {
+        const newContext = [];
+        const iterator = context[Symbol.iterator]();
+        for (let it = iterator.next(); !it.done; it = iterator.next()) {
+          newContext.push(it.value);
+        }
+        context = newContext;
+        for (let j = context.length; i < j; i++) {
+          execIteration(i, context[i], i, i === context.length - 1);
+        }
+      } else {
+        let priorKey;
+
+        Object.keys(context).forEach((key) => {
+          // We're running the iterations one step out of sync so we can detect
+          // the last iteration without have to scan the object twice and create
+          // an intermediate keys array.
+          if (priorKey !== undefined) {
+            execIteration(priorKey, context[priorKey], i - 1);
+          }
+          priorKey = key;
+          i++;
+        });
+        if (priorKey !== undefined) {
+          execIteration(priorKey, context[priorKey], i - 1, true);
+        }
+      }
+    }
+
+    if (i === 0) {
+      ret = inverse(this);
+    }
+
+    return ret;
+  });
+}

lib/handlebars/helpers/helper-missing.js

@@ -0,0 +1,15 @@
+import { Exception } from '@handlebars/parser';
+
+export default function (instance) {
+  instance.registerHelper('helperMissing', function (/* [args, ]options */) {
+    if (arguments.length === 1) {
+      // A missing field in a {{foo}} construct.
+      return undefined;
+    } else {
+      // Someone is actually trying to call something, blow up.
+      throw new Exception(
+        'Missing helper: "' + arguments[arguments.length - 1].name + '"'
+      );
+    }
+  });
+}

lib/handlebars/helpers/if.js

@@ -0,0 +1,33 @@
+import { Exception } from '@handlebars/parser';
+import { isEmpty, isFunction } from '../utils';
+
+export default function (instance) {
+  instance.registerHelper('if', function (conditional, options) {
+    if (arguments.length != 2) {
+      throw new Exception('#if requires exactly one argument');
+    }
+    if (isFunction(conditional)) {
+      conditional = conditional.call(this);
+    }
+
+    // Default behavior is to render the positive path if the value is truthy and not empty.
+    // The `includeZero` option may be set to treat the conditional as purely not empty based on the
+    // behavior of isEmpty. Effectively this determines if 0 is handled by the positive path or negative.
+    if ((!options.hash.includeZero && !conditional) || isEmpty(conditional)) {
+      return options.inverse(this);
+    } else {
+      return options.fn(this);
+    }
+  });
+
+  instance.registerHelper('unless', function (conditional, options) {
+    if (arguments.length != 2) {
+      throw new Exception('#unless requires exactly one argument');
+    }
+    return instance.helpers['if'].call(this, conditional, {
+      fn: options.inverse,
+      inverse: options.fn,
+      hash: options.hash,
+    });
+  });
+}

lib/handlebars/helpers/log.js

@@ -0,0 +1,19 @@
+export default function (instance) {
+  instance.registerHelper('log', function (/* message, options */) {
+    let args = [undefined],
+      options = arguments[arguments.length - 1];
+    for (let i = 0; i < arguments.length - 1; i++) {
+      args.push(arguments[i]);
+    }
+
+    let level = 1;
+    if (options.hash.level != null) {
+      level = options.hash.level;
+    } else if (options.data && options.data.level != null) {
+      level = options.data.level;
+    }
+    args[0] = level;
+
+    instance.log(...args);
+  });
+}

lib/handlebars/helpers/lookup.js

@@ -0,0 +1,9 @@
+export default function (instance) {
+  instance.registerHelper('lookup', function (obj, field, options) {
+    if (!obj) {
+      // Note for 5.0: Change to "obj == null" in 5.0
+      return obj;
+    }
+    return options.lookupProperty(obj, field);
+  });
+}

lib/handlebars/helpers/with.js

@@ -0,0 +1,26 @@
+import { Exception } from '@handlebars/parser';
+import { isEmpty, isFunction } from '../utils';
+
+export default function (instance) {
+  instance.registerHelper('with', function (context, options) {
+    if (arguments.length != 2) {
+      throw new Exception('#with requires exactly one argument');
+    }
+    if (isFunction(context)) {
+      context = context.call(this);
+    }
+
+    let fn = options.fn;
+
+    if (!isEmpty(context)) {
+      let data = options.data;
+
+      return fn(context, {
+        data: data,
+        blockParams: [context],
+      });
+    } else {
+      return options.inverse(this);
+    }
+  });
+}

lib/handlebars/internal/proto-access.js

@@ -0,0 +1,68 @@
+import { extend } from '../utils';
+import logger from '../logger';
+
+const loggedProperties = Object.create(null);
+
+export function createProtoAccessControl(runtimeOptions) {
+  // Create an object with "null"-prototype to avoid truthy results on
+  // prototype properties.
+  const propertyWhiteList = Object.create(null);
+  // eslint-disable-next-line no-proto
+  propertyWhiteList['__proto__'] = false;
+  extend(propertyWhiteList, runtimeOptions.allowedProtoProperties);
+
+  const methodWhiteList = Object.create(null);
+  methodWhiteList['constructor'] = false;
+  methodWhiteList['__defineGetter__'] = false;
+  methodWhiteList['__defineSetter__'] = false;
+  methodWhiteList['__lookupGetter__'] = false;
+  extend(methodWhiteList, runtimeOptions.allowedProtoMethods);
+
+  return {
+    properties: {
+      whitelist: propertyWhiteList,
+      defaultValue: runtimeOptions.allowProtoPropertiesByDefault,
+    },
+    methods: {
+      whitelist: methodWhiteList,
+      defaultValue: runtimeOptions.allowProtoMethodsByDefault,
+    },
+  };
+}
+
+export function resultIsAllowed(result, protoAccessControl, propertyName) {
+  if (typeof result === 'function') {
+    return checkWhiteList(protoAccessControl.methods, propertyName);
+  } else {
+    return checkWhiteList(protoAccessControl.properties, propertyName);
+  }
+}
+
+function checkWhiteList(protoAccessControlForType, propertyName) {
+  if (protoAccessControlForType.whitelist[propertyName] !== undefined) {
+    return protoAccessControlForType.whitelist[propertyName] === true;
+  }
+  if (protoAccessControlForType.defaultValue !== undefined) {
+    return protoAccessControlForType.defaultValue;
+  }
+  logUnexpectedPropertyAccessOnce(propertyName);
+  return false;
+}
+
+function logUnexpectedPropertyAccessOnce(propertyName) {
+  if (loggedProperties[propertyName] !== true) {
+    loggedProperties[propertyName] = true;
+    logger.log(
+      'error',
+      `Handlebars: Access has been denied to resolve the property "${propertyName}" because it is not an "own property" of its parent.\n` +
+        `You can add a runtime option to disable the check or this warning:\n` +
+        `See https://handlebarsjs.com/api-reference/runtime-options.html#options-to-control-prototype-access for details`
+    );
+  }
+}
+
+export function resetLoggedProperties() {
+  Object.keys(loggedProperties).forEach((propertyName) => {
+    delete loggedProperties[propertyName];
+  });
+}

lib/handlebars/internal/wrapHelper.js

@@ -0,0 +1,13 @@
+export function wrapHelper(helper, transformOptionsFn) {
+  if (typeof helper !== 'function') {
+    // This should not happen, but apparently it does in https://github.com/handlebars-lang/handlebars.js/issues/1639
+    // We try to make the wrapper least-invasive by not wrapping it, if the helper is not a function.
+    return helper;
+  }
+  let wrapper = function (/* dynamic arguments */) {
+    const options = arguments[arguments.length - 1];
+    arguments[arguments.length - 1] = transformOptionsFn(options);
+    return helper.apply(this, arguments);
+  };
+  return wrapper;
+}

lib/handlebars/logger.js

@@ -0,0 +1,39 @@
+import { indexOf } from './utils';
+
+let logger = {
+  methodMap: ['debug', 'info', 'warn', 'error'],
+  level: 'info',
+
+  // Maps a given level value to the `methodMap` indexes above.
+  lookupLevel: function (level) {
+    if (typeof level === 'string') {
+      let levelMap = indexOf(logger.methodMap, level.toLowerCase());
+      if (levelMap >= 0) {
+        level = levelMap;
+      } else {
+        level = parseInt(level, 10);
+      }
+    }
+
+    return level;
+  },
+
+  // Can be overridden in the host environment
+  log: function (level, ...message) {
+    level = logger.lookupLevel(level);
+
+    if (
+      typeof console !== 'undefined' &&
+      logger.lookupLevel(logger.level) <= level
+    ) {
+      let method = logger.methodMap[level];
+      // eslint-disable-next-line no-console
+      if (!console[method]) {
+        method = 'log';
+      }
+      console[method](...message); // eslint-disable-line no-console
+    }
+  },
+};
+
+export default logger;

lib/handlebars/no-conflict.js

@@ -0,0 +1,11 @@
+export default function (Handlebars) {
+  let $Handlebars = globalThis.Handlebars;
+
+  /* v8 ignore next */
+  Handlebars.noConflict = function () {
+    if (globalThis.Handlebars === Handlebars) {
+      globalThis.Handlebars = $Handlebars;
+    }
+    return Handlebars;
+  };
+}

lib/handlebars/runtime.js

@@ -1,92 +1,428 @@
-exports.attach = function(Handlebars) {
+import { Exception } from '@handlebars/parser';
+import * as Utils from './utils';
+import {
+  COMPILER_REVISION,
+  createFrame,
+  LAST_COMPATIBLE_COMPILER_REVISION,
+  REVISION_CHANGES,
+} from './base';
+import { moveHelperToHooks } from './helpers';
+import { wrapHelper } from './internal/wrapHelper';
+import {
+  createProtoAccessControl,
+  resultIsAllowed,
+} from './internal/proto-access';
 
-// BEGIN(BROWSER)
+export function checkRevision(compilerInfo) {
+  const compilerRevision = (compilerInfo && compilerInfo[0]) || 1,
+    currentRevision = COMPILER_REVISION;
 
-Handlebars.VM = {
-  template: function(templateSpec) {
-    // Just add water
-    var container = {
-      escapeExpression: Handlebars.Utils.escapeExpression,
-      invokePartial: Handlebars.VM.invokePartial,
-      programs: [],
-      program: function(i, fn, data) {
-        var programWrapper = this.programs[i];
-        if(data) {
-          return Handlebars.VM.program(fn, data);
-        } else if(programWrapper) {
-          return programWrapper;
-        } else {
-          programWrapper = this.programs[i] = Handlebars.VM.program(fn);
-          return programWrapper;
-        }
-      },
-      programWithDepth: Handlebars.VM.programWithDepth,
-      noop: Handlebars.VM.noop,
-      compilerInfo: null
-    };
-
-    return function(context, options) {
-      options = options || {};
-      var result = templateSpec.call(container, Handlebars, context, options.helpers, options.partials, options.data);
-
-      var compilerInfo = container.compilerInfo || [],
-          compilerRevision = compilerInfo[0] || 1,
-          currentRevision = Handlebars.COMPILER_REVISION;
-
-      if (compilerRevision !== currentRevision) {
-        if (compilerRevision < currentRevision) {
-          var runtimeVersions = Handlebars.REVISION_CHANGES[currentRevision],
-              compilerVersions = Handlebars.REVISION_CHANGES[compilerRevision];
-          throw "Template was precompiled with an older version of Handlebars than the current runtime. "+
-                "Please update your precompiler to a newer version ("+runtimeVersions+") or downgrade your runtime to an older version ("+compilerVersions+").";
-        } else {
-          // Use the embedded version info since the runtime doesn't know about this revision yet
-          throw "Template was precompiled with a newer version of Handlebars than the current runtime. "+
-                "Please update your runtime to a newer version ("+compilerInfo[1]+").";
+  if (
+    compilerRevision >= LAST_COMPATIBLE_COMPILER_REVISION &&
+    compilerRevision <= COMPILER_REVISION
+  ) {
+    return;
+  }
+
+  if (compilerRevision < LAST_COMPATIBLE_COMPILER_REVISION) {
+    const runtimeVersions = REVISION_CHANGES[currentRevision],
+      compilerVersions = REVISION_CHANGES[compilerRevision];
+    throw new Exception(
+      'Template was precompiled with an older version of Handlebars than the current runtime. ' +
+        'Please update your precompiler to a newer version (' +
+        runtimeVersions +
+        ') or downgrade your runtime to an older version (' +
+        compilerVersions +
+        ').'
+    );
+  } else {
+    // Use the embedded version info since the runtime doesn't know about this revision yet
+    throw new Exception(
+      'Template was precompiled with a newer version of Handlebars than the current runtime. ' +
+        'Please update your runtime to a newer version (' +
+        compilerInfo[1] +
+        ').'
+    );
+  }
+}
+
+export function template(templateSpec, env) {
+  /* v8 ignore next */
+  if (!env) {
+    throw new Exception('No environment passed to template');
+  }
+  if (!templateSpec || !templateSpec.main) {
+    throw new Exception('Unknown template object: ' + typeof templateSpec);
+  }
+
+  templateSpec.main.decorator = templateSpec.main_d;
+
+  // Note: Using env.VM references rather than local var references throughout this section to allow
+  // for external users to override these as pseudo-supported APIs.
+  env.VM.checkRevision(templateSpec.compiler);
+
+  // backwards compatibility for precompiled templates with compiler-version 7 (<4.3.0)
+  const templateWasPrecompiledWithCompilerV7 =
+    templateSpec.compiler && templateSpec.compiler[0] === 7;
+
+  function invokePartialWrapper(partial, context, options) {
+    if (options.hash) {
+      context = Utils.extend({}, context, options.hash);
+    }
+    partial = env.VM.resolvePartial.call(this, partial, context, options);
+
+    options.hooks = this.hooks;
+    options.protoAccessControl = this.protoAccessControl;
+
+    let result = env.VM.invokePartial.call(this, partial, context, options);
+
+    if (result == null && env.compile) {
+      options.partials[options.name] = env.compile(
+        partial,
+        templateSpec.compilerOptions,
+        env
+      );
+      result = options.partials[options.name](context, options);
+    }
+    if (result != null) {
+      if (options.indent) {
+        let lines = result.split('\n');
+        for (let i = 0, l = lines.length; i < l; i++) {
+          if (!lines[i] && i + 1 === l) {
+            break;
+          }
+
+          lines[i] = options.indent + lines[i];
         }
+        result = lines.join('\n');
       }
-
       return result;
-    };
-  },
-
-  programWithDepth: function(fn, data, $depth) {
-    var args = Array.prototype.slice.call(arguments, 2);
-
-    return function(context, options) {
-      options = options || {};
-
-      return fn.apply(this, [context, options.data || data].concat(args));
-    };
-  },
-  program: function(fn, data) {
-    return function(context, options) {
-      options = options || {};
-
-      return fn(context, options.data || data);
-    };
-  },
-  noop: function() { return ""; },
-  invokePartial: function(partial, name, context, helpers, partials, data) {
-    var options = { helpers: helpers, partials: partials, data: data };
-
-    if(partial === undefined) {
-      throw new Handlebars.Exception("The partial " + name + " could not be found");
-    } else if(partial instanceof Function) {
-      return partial(context, options);
-    } else if (!Handlebars.compile) {
-      throw new Handlebars.Exception("The partial " + name + " could not be compiled when running in runtime-only mode");
     } else {
-      partials[name] = Handlebars.compile(partial, {data: data !== undefined});
-      return partials[name](context, options);
+      throw new Exception(
+        'The partial ' +
+          options.name +
+          ' could not be compiled when running in runtime-only mode'
+      );
     }
   }
-};
 
-Handlebars.template = Handlebars.VM.template;
+  // Just add water
+  let container = {
+    strict: function (obj, name, loc) {
+      if (!obj || !(name in obj)) {
+        throw new Exception('"' + name + '" not defined in ' + obj, {
+          loc: loc,
+        });
+      }
+      return container.lookupProperty(obj, name);
+    },
+    lookupProperty: function (parent, propertyName) {
+      if (Utils.isMap(parent)) {
+        return parent.get(propertyName);
+      }
 
-// END(BROWSER)
+      let result = parent[propertyName];
+      if (result == null) {
+        return result;
+      }
+      if (Object.prototype.hasOwnProperty.call(parent, propertyName)) {
+        return result;
+      }
 
-return Handlebars;
+      if (resultIsAllowed(result, container.protoAccessControl, propertyName)) {
+        return result;
+      }
+      return undefined;
+    },
+    lookup: function (depths, name) {
+      const len = depths.length;
+      for (let i = 0; i < len; i++) {
+        let result = depths[i] && container.lookupProperty(depths[i], name);
+        if (result != null) {
+          return depths[i][name];
+        }
+      }
+    },
+    lambda: function (current, context) {
+      return typeof current === 'function' ? current.call(context) : current;
+    },
 
-};
+    escapeExpression: Utils.escapeExpression,
+    invokePartial: invokePartialWrapper,
+
+    fn: function (i) {
+      let ret = templateSpec[i];
+      ret.decorator = templateSpec[i + '_d'];
+      return ret;
+    },
+
+    programs: [],
+    program: function (i, data, declaredBlockParams, blockParams, depths) {
+      let programWrapper = this.programs[i],
+        fn = this.fn(i);
+      if (data || depths || blockParams || declaredBlockParams) {
+        programWrapper = wrapProgram(
+          this,
+          i,
+          fn,
+          data,
+          declaredBlockParams,
+          blockParams,
+          depths
+        );
+      } else if (!programWrapper) {
+        programWrapper = this.programs[i] = wrapProgram(this, i, fn);
+      }
+      return programWrapper;
+    },
+
+    data: function (value, depth) {
+      while (value && depth--) {
+        value = value._parent;
+      }
+      return value;
+    },
+    mergeIfNeeded: function (param, common) {
+      let obj = param || common;
+
+      if (param && common && param !== common) {
+        obj = Utils.extend({}, common, param);
+      }
+
+      return obj;
+    },
+    // An empty object to use as replacement for null-contexts
+    nullContext: Object.seal({}),
+
+    noop: env.VM.noop,
+    compilerInfo: templateSpec.compiler,
+  };
+
+  function ret(context, options = {}) {
+    let data = options.data;
+
+    _setup(options);
+    if (!options.partial && templateSpec.useData) {
+      data = initData(context, data);
+    }
+    let depths,
+      blockParams = templateSpec.useBlockParams ? [] : undefined;
+    if (templateSpec.useDepths) {
+      if (options.depths) {
+        depths =
+          context != options.depths[0]
+            ? [context].concat(options.depths)
+            : options.depths;
+      } else {
+        depths = [context];
+      }
+    }
+
+    function main(context /*, options*/) {
+      return (
+        '' +
+        templateSpec.main(
+          container,
+          context,
+          container.helpers,
+          container.partials,
+          data,
+          blockParams,
+          depths
+        )
+      );
+    }
+
+    main = executeDecorators(
+      templateSpec.main,
+      main,
+      container,
+      options.depths || [],
+      data,
+      blockParams
+    );
+    return main(context, options);
+  }
+
+  ret.isTop = true;
+
+  function _setup(options) {
+    if (!options.partial) {
+      let mergedHelpers = {};
+      addHelpers(mergedHelpers, env.helpers, container);
+      addHelpers(mergedHelpers, options.helpers, container);
+      container.helpers = mergedHelpers;
+
+      if (templateSpec.usePartial) {
+        // Use mergeIfNeeded here to prevent compiling global partials multiple times
+        container.partials = container.mergeIfNeeded(
+          options.partials,
+          env.partials
+        );
+      }
+      if (templateSpec.usePartial || templateSpec.useDecorators) {
+        container.decorators = Utils.extend(
+          {},
+          env.decorators,
+          options.decorators
+        );
+      }
+
+      container.hooks = {};
+      container.protoAccessControl = createProtoAccessControl(options);
+
+      let keepHelperInHelpers =
+        options.allowCallsToHelperMissing ||
+        templateWasPrecompiledWithCompilerV7;
+      moveHelperToHooks(container, 'helperMissing', keepHelperInHelpers);
+      moveHelperToHooks(container, 'blockHelperMissing', keepHelperInHelpers);
+    } else {
+      container.protoAccessControl = options.protoAccessControl; // internal option
+      container.helpers = options.helpers;
+      container.partials = options.partials;
+      container.decorators = options.decorators;
+      container.hooks = options.hooks;
+    }
+  }
+
+  return ret;
+}
+
+export function wrapProgram(
+  container,
+  i,
+  fn,
+  data,
+  declaredBlockParams,
+  blockParams,
+  depths
+) {
+  function prog(context, options = {}) {
+    let currentDepths = depths;
+    if (
+      depths &&
+      context != depths[0] &&
+      !(context === container.nullContext && depths[0] === null)
+    ) {
+      currentDepths = [context].concat(depths);
+    }
+
+    return fn(
+      container,
+      context,
+      container.helpers,
+      container.partials,
+      options.data || data,
+      blockParams && [options.blockParams].concat(blockParams),
+      currentDepths
+    );
+  }
+
+  prog = executeDecorators(fn, prog, container, depths, data, blockParams);
+
+  prog.program = i;
+  prog.depth = depths ? depths.length : 0;
+  prog.blockParams = declaredBlockParams || 0;
+  return prog;
+}
+
+/**
+ * This is currently part of the official API, therefore implementation details should not be changed.
+ */
+export function resolvePartial(partial, context, options) {
+  if (!partial) {
+    if (options.name === '@partial-block') {
+      partial = options.data['partial-block'];
+    } else {
+      partial = options.partials[options.name];
+    }
+  } else if (!partial.call && !options.name) {
+    // This is a dynamic partial that returned a string
+    options.name = partial;
+    partial = options.partials[partial];
+  }
+  return partial;
+}
+
+export function invokePartial(partial, context, options) {
+  // Use the current closure context to save the partial-block if this partial
+  const currentPartialBlock = options.data && options.data['partial-block'];
+  options.partial = true;
+
+  let partialBlock;
+  if (options.fn && options.fn !== noop) {
+    options.data = createFrame(options.data);
+    // Wrapper function to get access to currentPartialBlock from the closure
+    let fn = options.fn;
+    partialBlock = options.data['partial-block'] = function partialBlockWrapper(
+      context,
+      options = {}
+    ) {
+      // Restore the partial-block from the closure for the execution of the block
+      // i.e. the part inside the block of the partial call.
+      options.data = createFrame(options.data);
+      options.data['partial-block'] = currentPartialBlock;
+      return fn(context, options);
+    };
+    if (fn.partials) {
+      options.partials = Utils.extend({}, options.partials, fn.partials);
+    }
+  }
+
+  if (partial === undefined && partialBlock) {
+    partial = partialBlock;
+  }
+
+  if (partial === undefined) {
+    throw new Exception(
+      'The partial "' + options.name + '" could not be found'
+    );
+  } else if (partial instanceof Function) {
+    return partial(context, options);
+  }
+}
+
+export function noop() {
+  return '';
+}
+
+function initData(context, data) {
+  if (!data || !('root' in data)) {
+    data = data ? createFrame(data) : {};
+    data.root = context;
+  }
+  return data;
+}
+
+function executeDecorators(fn, prog, container, depths, data, blockParams) {
+  if (fn.decorator) {
+    let props = {};
+    prog = fn.decorator(
+      prog,
+      props,
+      container,
+      depths && depths[0],
+      data,
+      blockParams,
+      depths
+    );
+    Utils.extend(prog, props);
+  }
+  return prog;
+}
+
+function addHelpers(mergedHelpers, helpers, container) {
+  if (!helpers) return;
+  Object.keys(helpers).forEach((helperName) => {
+    let helper = helpers[helperName];
+    mergedHelpers[helperName] = passLookupPropertyOption(helper, container);
+  });
+}
+
+function passLookupPropertyOption(helper, container) {
+  const lookupProperty = container.lookupProperty;
+  return wrapHelper(helper, (options) => {
+    options.lookupProperty = lookupProperty;
+    return options;
+  });
+}

lib/handlebars/safe-string.js

@@ -0,0 +1,10 @@
+// Build out our basic SafeString type
+function SafeString(string) {
+  this.string = string;
+}
+
+SafeString.prototype.toString = SafeString.prototype.toHTML = function () {
+  return '' + this.string;
+};
+
+export default SafeString;

lib/handlebars/utils.js

@@ -1,70 +1,98 @@
-exports.attach = function(Handlebars) {
-
-// BEGIN(BROWSER)
-
-var errorProps = ['description', 'fileName', 'lineNumber', 'message', 'name', 'number', 'stack'];
-
-Handlebars.Exception = function(message) {
-  var tmp = Error.prototype.constructor.apply(this, arguments);
-
-  // Unfortunately errors are not enumerable in Chrome (at least), so `for prop in tmp` doesn't work.
-  for (var idx = 0; idx < errorProps.length; idx++) {
-    this[errorProps[idx]] = tmp[errorProps[idx]];
-  }
-};
-Handlebars.Exception.prototype = new Error();
-
-// Build out our basic SafeString type
-Handlebars.SafeString = function(string) {
-  this.string = string;
-};
-Handlebars.SafeString.prototype.toString = function() {
-  return this.string.toString();
+const escape = {
+  '&': '&amp;',
+  '<': '&lt;',
+  '>': '&gt;',
+  '"': '&quot;',
+  "'": '&#x27;',
+  '`': '&#x60;',
+  '=': '&#x3D;',
 };
 
-(function() {
-  var escape = {
-    "&": "&amp;",
-    "<": "&lt;",
-    ">": "&gt;",
-    '"': "&quot;",
-    "'": "&#x27;",
-    "`": "&#x60;"
-  };
+const badChars = /[&<>"'`=]/g,
+  possible = /[&<>"'`=]/;
 
-  var badChars = /[&<>"'`]/g;
-  var possible = /[&<>"'`]/;
+function escapeChar(chr) {
+  return escape[chr];
+}
 
-  var escapeChar = function(chr) {
-    return escape[chr] || "&amp;";
-  };
-
-  Handlebars.Utils = {
-    escapeExpression: function(string) {
-      // don't escape SafeStrings, since they're already safe
-      if (string instanceof Handlebars.SafeString) {
-        return string.toString();
-      } else if (string == null || string === false) {
-        return "";
-      }
-
-      if(!possible.test(string)) { return string; }
-      return string.replace(badChars, escapeChar);
-    },
-
-    isEmpty: function(value) {
-      if (!value && value !== 0) {
-        return true;
-      } else if(Object.prototype.toString.call(value) === "[object Array]" && value.length === 0) {
-        return true;
-      } else {
-        return false;
+export function extend(obj /* , ...source */) {
+  for (let i = 1; i < arguments.length; i++) {
+    for (let key in arguments[i]) {
+      if (Object.prototype.hasOwnProperty.call(arguments[i], key)) {
+        obj[key] = arguments[i][key];
       }
     }
+  }
+
+  return obj;
+}
+
+export let toString = Object.prototype.toString;
+
+// Sourced from lodash
+// https://github.com/lodash/lodash/blob/4.17.21/LICENSE
+export function isFunction(value) {
+  return typeof value === 'function';
+}
+
+function testTag(name) {
+  const tag = '[object ' + name + ']';
+  return function (value) {
+    return value && typeof value === 'object'
+      ? toString.call(value) === tag
+      : false;
   };
-})();
+}
 
-// END(BROWSER)
+export const isArray = Array.isArray;
+export const isMap = testTag('Map');
+export const isSet = testTag('Set');
 
-return Handlebars;
-};
+// Older IE versions do not directly support indexOf so we must implement our own, sadly.
+export function indexOf(array, value) {
+  for (let i = 0, len = array.length; i < len; i++) {
+    if (array[i] === value) {
+      return i;
+    }
+  }
+  return -1;
+}
+
+export function escapeExpression(string) {
+  if (typeof string !== 'string') {
+    // don't escape SafeStrings, since they're already safe
+    if (string && string.toHTML) {
+      return string.toHTML();
+    } else if (string == null) {
+      return '';
+    } else if (!string) {
+      return string + '';
+    }
+
+    // Force a string conversion as this will be done by the append regardless and
+    // the regex test will do this transparently behind the scenes, causing issues if
+    // an object's to string has escaped characters in it.
+    string = '' + string;
+  }
+
+  if (!possible.test(string)) {
+    return string;
+  }
+  return string.replace(badChars, escapeChar);
+}
+
+export function isEmpty(value) {
+  if (!value && value !== 0) {
+    return true;
+  } else if (isArray(value) && value.length === 0) {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+export function createFrame(object) {
+  let frame = extend({}, object);
+  frame._parent = object;
+  return frame;
+}

lib/index.js

@@ -0,0 +1,25 @@
+// USAGE:
+// var handlebars = require('handlebars');
+/* eslint-disable no-var */
+
+// var local = handlebars.create();
+
+var handlebars = require('../dist/cjs/handlebars')['default'];
+
+var parser = require('@handlebars/parser');
+handlebars.PrintVisitor = parser.PrintVisitor;
+handlebars.print = parser.print;
+
+module.exports = handlebars;
+
+// Publish a Node.js require() handler for .handlebars and .hbs files
+function extension(module, filename) {
+  var fs = require('fs');
+  var templateString = fs.readFileSync(filename, 'utf8');
+  module.exports = handlebars.compile(templateString);
+}
+/* v8 ignore next 4 */
+if (typeof require !== 'undefined' && require.extensions) {
+  require.extensions['.handlebars'] = extension;
+  require.extensions['.hbs'] = extension;
+}

lib/precompiler.js

@@ -0,0 +1,344 @@
+/* eslint-disable no-console */
+import Async from 'neo-async';
+import fs from 'fs';
+import Handlebars from './handlebars';
+import { basename } from 'path';
+import { SourceMapConsumer, SourceNode } from 'source-map';
+
+module.exports.loadTemplates = function (opts, callback) {
+  loadStrings(opts, function (err, strings) {
+    if (err) {
+      callback(err);
+    } else {
+      loadFiles(opts, function (err, files) {
+        if (err) {
+          callback(err);
+        } else {
+          opts.templates = strings.concat(files);
+          callback(undefined, opts);
+        }
+      });
+    }
+  });
+};
+
+function loadStrings(opts, callback) {
+  let strings = arrayCast(opts.string),
+    names = arrayCast(opts.name);
+
+  if (names.length !== strings.length && strings.length > 1) {
+    return callback(
+      new Handlebars.Exception(
+        'Number of names did not match the number of string inputs'
+      )
+    );
+  }
+
+  Async.map(
+    strings,
+    function (string, callback) {
+      if (string !== '-') {
+        callback(undefined, string);
+      } else {
+        // Load from stdin
+        let buffer = '';
+        process.stdin.setEncoding('utf8');
+
+        process.stdin.on('data', function (chunk) {
+          buffer += chunk;
+        });
+        process.stdin.on('end', function () {
+          callback(undefined, buffer);
+        });
+      }
+    },
+    function (err, strings) {
+      strings = strings.map((string, index) => ({
+        name: names[index],
+        path: names[index],
+        source: string,
+      }));
+      callback(err, strings);
+    }
+  );
+}
+
+function loadFiles(opts, callback) {
+  // Build file extension pattern
+  let extension = (opts.extension || 'handlebars').replace(
+    /[\\^$*+?.():=!|{}\-[\]]/g,
+    function (arg) {
+      return '\\' + arg;
+    }
+  );
+  extension = new RegExp('\\.' + extension + '$');
+
+  let ret = [],
+    queue = (opts.files || []).map((template) => ({
+      template,
+      root: opts.root,
+    }));
+  Async.whilst(
+    () => queue.length,
+    function (callback) {
+      let { template: path, root } = queue.shift();
+
+      fs.stat(path, function (err, stat) {
+        if (err) {
+          return callback(
+            new Handlebars.Exception(`Unable to open template file "${path}"`)
+          );
+        }
+
+        if (stat.isDirectory()) {
+          opts.hasDirectory = true;
+
+          fs.readdir(path, function (err, children) {
+            /* v8 ignore next -- Race condition that being too lazy to test */
+            if (err) {
+              return callback(err);
+            }
+            children.forEach(function (file) {
+              let childPath = path + '/' + file;
+
+              if (
+                extension.test(childPath) ||
+                fs.statSync(childPath).isDirectory()
+              ) {
+                queue.push({ template: childPath, root: root || path });
+              }
+            });
+
+            callback();
+          });
+        } else {
+          fs.readFile(path, 'utf8', function (err, data) {
+            /* v8 ignore next -- Race condition that being too lazy to test */
+            if (err) {
+              return callback(err);
+            }
+
+            if (opts.bom && data.indexOf('\uFEFF') === 0) {
+              data = data.substring(1);
+            }
+
+            // Clean the template name
+            let name = path;
+            if (!root) {
+              name = basename(name);
+            } else if (name.indexOf(root) === 0) {
+              name = name.substring(root.length + 1);
+            }
+            name = name.replace(extension, '');
+
+            ret.push({
+              path: path,
+              name: name,
+              source: data,
+            });
+
+            callback();
+          });
+        }
+      });
+    },
+    function (err) {
+      if (err) {
+        callback(err);
+      } else {
+        callback(undefined, ret);
+      }
+    }
+  );
+}
+
+module.exports.cli = async function (opts) {
+  if (opts.version) {
+    console.log(Handlebars.VERSION);
+    return;
+  }
+
+  if (!opts.templates.length && !opts.hasDirectory) {
+    throw new Handlebars.Exception(
+      'Must define at least one template or directory.'
+    );
+  }
+
+  if (opts.simple && opts.min) {
+    throw new Handlebars.Exception('Unable to minimize simple output');
+  }
+
+  const multiple = opts.templates.length !== 1 || opts.hasDirectory;
+  if (opts.simple && multiple) {
+    throw new Handlebars.Exception(
+      'Unable to output multiple templates in simple mode'
+    );
+  }
+
+  // Force simple mode if we have only one template and it's unnamed.
+  if (
+    !opts.amd &&
+    !opts.commonjs &&
+    opts.templates.length === 1 &&
+    !opts.templates[0].name
+  ) {
+    opts.simple = true;
+  }
+
+  // Convert the known list into a hash
+  let known = {};
+  if (opts.known && !Array.isArray(opts.known)) {
+    opts.known = [opts.known];
+  }
+  if (opts.known) {
+    for (let i = 0, len = opts.known.length; i < len; i++) {
+      known[opts.known[i]] = true;
+    }
+  }
+
+  const objectName = opts.partial ? 'Handlebars.partials' : 'templates';
+
+  let output = new SourceNode();
+  if (!opts.simple) {
+    if (opts.amd) {
+      output.add(
+        "define(['" +
+          opts.handlebarPath +
+          'handlebars.runtime\'], function(Handlebars) {\n  Handlebars = Handlebars["default"];'
+      );
+    } else if (opts.commonjs) {
+      output.add('var Handlebars = require("' + opts.commonjs + '");');
+    } else {
+      output.add('(function() {\n');
+    }
+    output.add('  var template = Handlebars.template, templates = ');
+    if (opts.namespace) {
+      output.add(opts.namespace);
+      output.add(' = ');
+      output.add(opts.namespace);
+      output.add(' || ');
+    }
+    output.add('{};\n');
+  }
+
+  for (const template of opts.templates) {
+    let options = {
+      knownHelpers: known,
+      knownHelpersOnly: opts.o,
+    };
+
+    if (opts.map) {
+      options.srcName = template.path;
+    }
+    if (opts.data) {
+      options.data = true;
+    }
+
+    let precompiled = Handlebars.precompile(template.source, options);
+
+    // If we are generating a source map, we have to reconstruct the SourceNode object
+    if (opts.map) {
+      let consumer = await new SourceMapConsumer(precompiled.map);
+      precompiled = SourceNode.fromStringWithSourceMap(
+        precompiled.code,
+        consumer
+      );
+      consumer.destroy();
+    }
+
+    if (opts.simple) {
+      output.add([precompiled, '\n']);
+    } else {
+      if (!template.name) {
+        throw new Handlebars.Exception('Name missing for template');
+      }
+
+      if (opts.amd && !multiple) {
+        output.add('return ');
+      }
+      output.add([
+        objectName,
+        "['",
+        template.name,
+        "'] = template(",
+        precompiled,
+        ');\n',
+      ]);
+    }
+  }
+
+  // Output the content
+  if (!opts.simple) {
+    if (opts.amd) {
+      if (multiple) {
+        output.add(['return ', objectName, ';\n']);
+      }
+      output.add('});');
+    } else if (!opts.commonjs) {
+      output.add('})();');
+    }
+  }
+
+  if (opts.map) {
+    output.add('\n//# sourceMappingURL=' + opts.map + '\n');
+  }
+
+  output = output.toStringWithSourceMap();
+  output.map = output.map + '';
+
+  if (opts.min) {
+    output = minify(output, opts.map);
+  }
+
+  if (opts.map) {
+    fs.writeFileSync(opts.map, output.map, 'utf8');
+  }
+  output = output.code;
+
+  if (opts.output) {
+    fs.writeFileSync(opts.output, output, 'utf8');
+  } else {
+    console.log(output);
+  }
+};
+
+function arrayCast(value) {
+  value = value != null ? value : [];
+  if (!Array.isArray(value)) {
+    value = [value];
+  }
+  return value;
+}
+
+/**
+ * Run uglify to minify the compiled template, if uglify exists in the dependencies.
+ *
+ * We are using `require` instead of `import` here, because es6-modules do not allow
+ * dynamic imports and uglify-js is an optional dependency. Since we are inside NodeJS here, this
+ * should not be a problem.
+ *
+ * @param {string} output the compiled template
+ * @param {string} sourceMapFile the file to write the source map to.
+ */
+function minify(output, sourceMapFile) {
+  try {
+    // Try to resolve uglify-js in order to see if it does exist
+    require.resolve('uglify-js');
+  } catch (e) {
+    if (e.code !== 'MODULE_NOT_FOUND') {
+      // Something else seems to be wrong
+      throw e;
+    }
+    // it does not exist!
+    console.error(
+      'Code minimization is disabled due to missing uglify-js dependency'
+    );
+    return output;
+  }
+  return require('uglify-js').minify(output.code, {
+    sourceMap: {
+      content: output.map,
+      url: sourceMapFile,
+    },
+  });
+}

package.json

@@ -1,35 +1,129 @@
 {
   "name": "handlebars",
-  "description": "Extension of the Mustache logicless template language",
-  "version": "1.0.9",
-  "homepage": "http://www.handlebarsjs.com/",
+  "version": "5.0.0-alpha.1",
+  "description": "Handlebars provides the power necessary to let you build semantic templates effectively with no frustration",
   "keywords": [
-    "handlebars mustache template html"
+    "handlebars",
+    "html",
+    "mustache",
+    "template"
   ],
+  "homepage": "https://handlebarsjs.com/",
+  "license": "MIT",
+  "author": "Yehuda Katz",
   "repository": {
     "type": "git",
-    "url": "git://github.com/wycats/handlebars.js.git"
+    "url": "https://github.com/handlebars-lang/handlebars.js.git"
   },
-  "engines": {
-    "node": ">=0.4.7"
+  "bin": {
+    "handlebars": "bin/handlebars.mjs"
+  },
+  "files": [
+    "bin",
+    "dist/*.js",
+    "dist/cjs/**/*.js",
+    "lib",
+    "release-notes.md",
+    "runtime.js",
+    "types/*.d.ts",
+    "runtime.d.ts"
+  ],
+  "main": "lib/index.js",
+  "browser": "./dist/cjs/handlebars.js",
+  "types": "types/index.d.ts",
+  "scripts": {
+    "clean": "node -e \"require('fs').rmSync('dist',{recursive:true,force:true});require('fs').rmSync('tmp',{recursive:true,force:true})\"",
+    "build:cjs": "swc lib --out-dir dist/cjs --strip-leading-paths --ignore \"**/index.js\"",
+    "build:bundles": "rspack build",
+    "build": "npm run clean && npm run build:cjs && npm run build:bundles",
+    "release": "npm run build",
+    "publish:aws": "npm run build && npm run test:tasks && node tasks/publish-to-aws.js",
+    "format": "oxfmt --write . && oxlint --fix .",
+    "lint": "npm run lint:oxlint && npm run lint:format && npm run lint:types && npm run lint:compat",
+    "lint:oxlint": "oxlint --max-warnings 0 .",
+    "lint:format": "oxfmt --check .",
+    "lint:types": "tstyche",
+    "lint:compat": "eslint",
+    "test": "npm run build && vitest run --project node --project tasks --project rspack --coverage",
+    "test:browser": "vitest run --project browser",
+    "test:unit": "vitest run --project node",
+    "test:tasks": "vitest run --project tasks",
+    "test:publish": "npm run build && vitest run --project publish",
+    "test:browser-smoke": "playwright test --config tests/browser/playwright.config.js",
+    "test:serve": "npx serve -l 9999 .",
+    "test:integration": "npm run build && ./tests/integration/run-integration-tests.sh",
+    "bench": "node tests/bench/perf.mjs",
+    "bench:compare": "node tests/bench/compare.mjs",
+    "bench:size": "node tests/bench/size.mjs",
+    "--- combined tasks ---": "",
+    "check-before-pull-request": "concurrently --kill-others-on-fail npm:lint npm:test"
   },
   "dependencies": {
-    "optimist": "~0.3",
-    "uglify-js": "~1.2"
+    "@handlebars/parser": "^2.1.0",
+    "neo-async": "^2.6.2",
+    "source-map": "^0.7.6",
+    "yargs": "^18.0.0"
   },
   "devDependencies": {
-    "benchmark": "~1.0",
-    "dust": "~0.3",
-    "jison": "~0.3",
-    "mocha": "*",
-    "mustache": "~0.7.2"
+    "@aws-sdk/client-s3": "^3.1011.0",
+    "@playwright/test": "^1.58.2",
+    "@rspack/cli": "^1.7.8",
+    "@rspack/core": "^1.7.8",
+    "@swc/cli": "^0.8.0",
+    "@swc/core": "^1.15.18",
+    "@vitest/browser": "^4.0.18",
+    "@vitest/browser-playwright": "^4.0.18",
+    "@vitest/coverage-v8": "^4.0.18",
+    "cli-testlab": "^6.0.0",
+    "concurrently": "^5.0.0",
+    "eslint": "^10.0.3",
+    "eslint-plugin-compat": "^7.0.1",
+    "fs-extra": "^8.1.0",
+    "husky": "^3.1.0",
+    "lint-staged": "^16.3.2",
+    "mock-stdin": "^0.3.0",
+    "oxfmt": "^0.36.0",
+    "oxlint": "^1.51.0",
+    "semver": "^5.0.1",
+    "tinybench": "^6.0.0",
+    "tstyche": "^6.2.0",
+    "typescript": "^5.9.3",
+    "uglify-js": "^3.19.3",
+    "vitest": "^4.0.18"
   },
-  "main": "lib/handlebars.js",
-  "bin": {
-    "handlebars": "bin/handlebars"
+  "peerDependencies": {
+    "uglify-js": "^3.19.3"
   },
-  "scripts": {
-    "test": "node_modules/.bin/mocha -u qunit spec/qunit_spec.js"
+  "husky": {
+    "hooks": {
+      "pre-commit": "lint-staged"
+    }
   },
-  "optionalDependencies": {}
+  "lint-staged": {
+    "*.{js,css,json,md}": [
+      "oxfmt --write"
+    ],
+    "*.js": [
+      "oxlint --fix"
+    ]
+  },
+  "browserslist": [
+    "last 2 versions",
+    "Firefox ESR",
+    "not dead",
+    "not IE 11",
+    "maintained node versions"
+  ],
+  "engines": {
+    "node": ">=20"
+  },
+  "jspm": {
+    "main": "handlebars",
+    "directories": {
+      "lib": "dist/cjs"
+    },
+    "buildConfig": {
+      "minify": true
+    }
+  }
 }

rspack.config.js

@@ -0,0 +1,88 @@
+const { rspack } = require('@rspack/core');
+const path = require('path');
+const fs = require('fs');
+
+const pkg = require('./package.json');
+const license = fs.readFileSync(path.resolve(__dirname, 'LICENSE'), 'utf8');
+const banner = `/*!
+
+ @license magnet:?xt=urn:btih:d3d9a9a6595521f9666a5e94cc830dab83b65699&dn=expat.txt Expat
+ ${pkg.name} v${pkg.version}
+
+${license}
+*/`;
+
+function createConfig(entry, filename, minimize) {
+  const plugins = [];
+
+  if (!minimize) {
+    // For non-minified builds, use BannerPlugin to add the license header
+    plugins.push(new rspack.BannerPlugin({ banner, raw: true }));
+  }
+
+  return {
+    mode: minimize ? 'production' : 'none',
+    context: __dirname,
+    entry,
+    output: {
+      path: path.resolve(__dirname, 'dist'),
+      filename,
+      library: {
+        name: 'Handlebars',
+        type: 'umd',
+        export: 'default',
+      },
+      globalObject: 'this',
+      clean: false,
+    },
+    module: {
+      rules: [
+        {
+          test: /\.js$/,
+          exclude: /node_modules/,
+          use: {
+            loader: 'builtin:swc-loader',
+            options: {
+              jsc: {
+                parser: { syntax: 'ecmascript' },
+              },
+            },
+          },
+        },
+      ],
+    },
+    optimization: {
+      minimize,
+      minimizer: minimize
+        ? [
+            new rspack.SwcJsMinimizerRspackPlugin({
+              extractComments: false,
+              minimizerOptions: {
+                compress: { passes: 2 },
+                mangle: true,
+                format: {
+                  comments: false,
+                  // Prepend the license banner in the minified output
+                  preamble: banner,
+                },
+              },
+            }),
+          ]
+        : [],
+    },
+    plugins,
+    target: ['web', 'browserslist'],
+    devtool: false,
+  };
+}
+
+module.exports = [
+  createConfig('./lib/handlebars.js', 'handlebars.js', false),
+  createConfig('./lib/handlebars.runtime.js', 'handlebars.runtime.js', false),
+  createConfig('./lib/handlebars.js', 'handlebars.min.js', true),
+  createConfig(
+    './lib/handlebars.runtime.js',
+    'handlebars.runtime.min.js',
+    true
+  ),
+];

runtime.d.ts

@@ -0,0 +1,3 @@
+import Handlebars = require('handlebars');
+
+declare module 'handlebars/runtime' {}

runtime.js

@@ -0,0 +1,3 @@
+// Create a simple path alias to allow browserify to resolve
+// the runtime on a supported path.
+module.exports = require('./dist/cjs/handlebars.runtime')['default'];

spec/acceptance_spec.rb

@@ -1,101 +0,0 @@
-require "spec_helper"
-
-class TestContext
-  class TestModule
-    attr_reader :name, :tests
-
-    def initialize(name)
-      @name = name
-      @tests = []
-    end
-  end
-
-  attr_reader :modules
-
-  def initialize
-    @modules = []
-  end
-
-  def module(name)
-    @modules << TestModule.new(name)
-  end
-
-  def test(name, function)
-    @modules.last.tests << [name, function]
-  end
-end
-
-test_context = TestContext.new
-js_context = Handlebars::Spec::CONTEXT
-
-Module.new do
-  extend Test::Unit::Assertions
-
-  def self.js_backtrace(context)
-    begin
-      context.eval("throw")
-    rescue V8::JSError => e
-      return e.backtrace(:javascript)
-    end
-  end
-
-  js_context["p"] = proc do |this, str|
-    p str
-  end
-
-  js_context["ok"] = proc do |this, ok, message|
-    js_context["$$RSPEC1$$"] = ok
-
-    result = js_context.eval("!!$$RSPEC1$$")
-
-    message ||= "#{ok} was not truthy"
-
-    unless result
-      backtrace = js_backtrace(js_context)
-      message << "\n#{backtrace.join("\n")}"
-    end
-
-    assert result, message
-  end
-
-  js_context["equals"] = proc do |this, first, second, message|
-    js_context["$$RSPEC1$$"] = first
-    js_context["$$RSPEC2$$"] = second
-
-    result = js_context.eval("$$RSPEC1$$ == $$RSPEC2$$")
-
-    additional_message = "#{first.inspect} did not == #{second.inspect}"
-    message = message ? "#{message} (#{additional_message})" : additional_message
-
-    unless result
-      backtrace = js_backtrace(js_context)
-      message << "\n#{backtrace.join("\n")}"
-    end
-
-    assert result, message
-  end
-
-  js_context["equal"] = js_context["equals"]
-
-  js_context["suite"] = proc do |this, name|
-    test_context.module(name)
-  end
-
-  js_context["test"] = proc do |this, name, function|
-    test_context.test(name, function)
-  end
-
-  local = Regexp.escape(File.expand_path(Dir.pwd))
-  qunit_spec = File.expand_path("../qunit_spec.js", __FILE__)
-  js_context.load(qunit_spec.sub(/^#{local}\//, ''))
-end
-
-test_context.modules.each do |mod|
-  describe mod.name do
-    mod.tests.each do |name, function|
-      it name do
-        function.call
-      end
-    end
-  end
-end

spec/artifacts/bom.handlebars

@@ -0,0 +1 @@
+a

spec/artifacts/example_1.handlebars

@@ -0,0 +1 @@
+{{foo}}

spec/artifacts/example_2.hbs

@@ -0,0 +1 @@
+Hello, {{name}}!

spec/artifacts/known.helpers.handlebars

@@ -0,0 +1,6 @@
+{{#someHelper true}}
+ <div>Some known helper</div>
+    {{#anotherHelper true}}
+    <div>Another known helper</div>
+    {{/anotherHelper}}
+{{/someHelper}}

spec/artifacts/non.default.extension.hbs

@@ -0,0 +1 @@
+<div>This is a test</div>

spec/artifacts/partial.template.handlebars

@@ -0,0 +1 @@
+<div>Test Partial</div>

spec/ast.js

@@ -0,0 +1,180 @@
+describe('ast', function () {
+  if (!Handlebars.AST) {
+    return;
+  }
+
+  var AST = Handlebars.AST;
+
+  describe('BlockStatement', function () {
+    it('should throw on mustache mismatch', function () {
+      expect(function () {
+        handlebarsEnv.parse('\n  {{#foo}}{{/bar}}');
+      }).toThrow("foo doesn't match bar - 2:5");
+    });
+  });
+
+  describe('helpers', function () {
+    describe('#helperExpression', function () {
+      it('should handle mustache statements', function () {
+        expect(
+          AST.helpers.helperExpression({
+            type: 'MustacheStatement',
+            params: [],
+            hash: undefined,
+          })
+        ).toBe(false);
+        expect(
+          AST.helpers.helperExpression({
+            type: 'MustacheStatement',
+            params: [1],
+            hash: undefined,
+          })
+        ).toBe(true);
+        expect(
+          AST.helpers.helperExpression({
+            type: 'MustacheStatement',
+            params: [],
+            hash: {},
+          })
+        ).toBe(true);
+      });
+      it('should handle block statements', function () {
+        expect(
+          AST.helpers.helperExpression({
+            type: 'BlockStatement',
+            params: [],
+            hash: undefined,
+          })
+        ).toBe(false);
+        expect(
+          AST.helpers.helperExpression({
+            type: 'BlockStatement',
+            params: [1],
+            hash: undefined,
+          })
+        ).toBe(true);
+        expect(
+          AST.helpers.helperExpression({
+            type: 'BlockStatement',
+            params: [],
+            hash: {},
+          })
+        ).toBe(true);
+      });
+      it('should handle subexpressions', function () {
+        expect(AST.helpers.helperExpression({ type: 'SubExpression' })).toBe(
+          true
+        );
+      });
+      it('should work with non-helper nodes', function () {
+        expect(AST.helpers.helperExpression({ type: 'Program' })).toBe(false);
+
+        expect(AST.helpers.helperExpression({ type: 'PartialStatement' })).toBe(
+          false
+        );
+        expect(AST.helpers.helperExpression({ type: 'ContentStatement' })).toBe(
+          false
+        );
+        expect(AST.helpers.helperExpression({ type: 'CommentStatement' })).toBe(
+          false
+        );
+
+        expect(AST.helpers.helperExpression({ type: 'PathExpression' })).toBe(
+          false
+        );
+
+        expect(AST.helpers.helperExpression({ type: 'StringLiteral' })).toBe(
+          false
+        );
+        expect(AST.helpers.helperExpression({ type: 'NumberLiteral' })).toBe(
+          false
+        );
+        expect(AST.helpers.helperExpression({ type: 'BooleanLiteral' })).toBe(
+          false
+        );
+        expect(AST.helpers.helperExpression({ type: 'UndefinedLiteral' })).toBe(
+          false
+        );
+        expect(AST.helpers.helperExpression({ type: 'NullLiteral' })).toBe(
+          false
+        );
+
+        expect(AST.helpers.helperExpression({ type: 'Hash' })).toBe(false);
+        expect(AST.helpers.helperExpression({ type: 'HashPair' })).toBe(false);
+      });
+    });
+  });
+
+  describe('Line Numbers', function () {
+    var ast, body;
+
+    function testColumns(node, firstLine, lastLine, firstColumn, lastColumn) {
+      expect(node.loc.start.line).toBe(firstLine);
+      expect(node.loc.start.column).toBe(firstColumn);
+      expect(node.loc.end.line).toBe(lastLine);
+      expect(node.loc.end.column).toBe(lastColumn);
+    }
+
+    ast = Handlebars.parse(
+      'line 1 {{line1Token}}\n' + // 1
+        ' line 2 {{line2token}}\n' + // 2
+        ' line 3 {{#blockHelperOnLine3}}\n' + // 3
+        'line 4{{line4token}}\n' + // 4
+        'line5{{else}}\n' + // 5
+        '{{line6Token}}\n' + // 6
+        '{{/blockHelperOnLine3}}\n' + // 7
+        '{{#open}}\n' + // 8
+        '{{else inverse}}\n' + // 9
+        '{{else}}\n' + // 10
+        '{{/open}}'
+    ); // 11
+    body = ast.body;
+
+    it('gets ContentNode line numbers', function () {
+      var contentNode = body[0];
+      testColumns(contentNode, 1, 1, 0, 7);
+    });
+
+    it('gets MustacheStatement line numbers', function () {
+      var mustacheNode = body[1];
+      testColumns(mustacheNode, 1, 1, 7, 21);
+    });
+
+    it('gets line numbers correct when newlines appear', function () {
+      testColumns(body[2], 1, 2, 21, 8);
+    });
+
+    it('gets MustacheStatement line numbers correct across newlines', function () {
+      var secondMustacheStatement = body[3];
+      testColumns(secondMustacheStatement, 2, 2, 8, 22);
+    });
+
+    it('gets the block helper information correct', function () {
+      var blockHelperNode = body[5];
+      testColumns(blockHelperNode, 3, 7, 8, 23);
+    });
+
+    it('correctly records the line numbers the program of a block helper', function () {
+      var blockHelperNode = body[5],
+        program = blockHelperNode.program;
+
+      testColumns(program, 3, 5, 31, 5);
+    });
+
+    it('correctly records the line numbers of an inverse of a block helper', function () {
+      var blockHelperNode = body[5],
+        inverse = blockHelperNode.inverse;
+
+      testColumns(inverse, 5, 7, 13, 0);
+    });
+
+    it('correctly records the line number of chained inverses', function () {
+      var chainInverseNode = body[7];
+
+      testColumns(chainInverseNode.program, 8, 9, 9, 0);
+      testColumns(chainInverseNode.inverse, 9, 10, 16, 0);
+      testColumns(chainInverseNode.inverse.body[0].program, 9, 10, 16, 0);
+      testColumns(chainInverseNode.inverse.body[0].inverse, 10, 11, 8, 0);
+    });
+  });
+});

spec/basic.js

@@ -0,0 +1,575 @@
+describe('basic context', function () {
+  it('most basic', function () {
+    expectTemplate('{{foo}}').withInput({ foo: 'foo' }).toCompileTo('foo');
+  });
+
+  it('escaping', function () {
+    expectTemplate('\\{{foo}}')
+      .withInput({ foo: 'food' })
+      .toCompileTo('{{foo}}');
+
+    expectTemplate('content \\{{foo}}')
+      .withInput({ foo: 'food' })
+      .toCompileTo('content {{foo}}');
+
+    expectTemplate('\\\\{{foo}}')
+      .withInput({ foo: 'food' })
+      .toCompileTo('\\food');
+
+    expectTemplate('content \\\\{{foo}}')
+      .withInput({ foo: 'food' })
+      .toCompileTo('content \\food');
+
+    expectTemplate('\\\\ {{foo}}')
+      .withInput({ foo: 'food' })
+      .toCompileTo('\\\\ food');
+  });
+
+  it('compiling with a basic context', function () {
+    expectTemplate('Goodbye\n{{cruel}}\n{{world}}!')
+      .withInput({
+        cruel: 'cruel',
+        world: 'world',
+      })
+      .withMessage('It works if all the required keys are provided')
+      .toCompileTo('Goodbye\ncruel\nworld!');
+  });
+
+  it('compiling with a string context', function () {
+    expectTemplate('{{.}}{{length}}').withInput('bye').toCompileTo('bye3');
+  });
+
+  it('compiling with an undefined context', function () {
+    expectTemplate('Goodbye\n{{cruel}}\n{{world.bar}}!')
+      .withInput(undefined)
+      .toCompileTo('Goodbye\n\n!');
+
+    expectTemplate('{{#unless foo}}Goodbye{{../test}}{{test2}}{{/unless}}')
+      .withInput(undefined)
+      .toCompileTo('Goodbye');
+  });
+
+  it('comments', function () {
+    expectTemplate('{{! Goodbye}}Goodbye\n{{cruel}}\n{{world}}!')
+      .withInput({
+        cruel: 'cruel',
+        world: 'world',
+      })
+      .withMessage('comments are ignored')
+      .toCompileTo('Goodbye\ncruel\nworld!');
+
+    expectTemplate('    {{~! comment ~}}      blah').toCompileTo('blah');
+
+    expectTemplate('    {{~!-- long-comment --~}}      blah').toCompileTo(
+      'blah'
+    );
+
+    expectTemplate('    {{! comment ~}}      blah').toCompileTo('    blah');
+
+    expectTemplate('    {{!-- long-comment --~}}      blah').toCompileTo(
+      '    blah'
+    );
+
+    expectTemplate('    {{~! comment}}      blah').toCompileTo('      blah');
+
+    expectTemplate('    {{~!-- long-comment --}}      blah').toCompileTo(
+      '      blah'
+    );
+  });
+
+  it('boolean', function () {
+    var string = '{{#goodbye}}GOODBYE {{/goodbye}}cruel {{world}}!';
+    expectTemplate(string)
+      .withInput({
+        goodbye: true,
+        world: 'world',
+      })
+      .withMessage('booleans show the contents when true')
+      .toCompileTo('GOODBYE cruel world!');
+
+    expectTemplate(string)
+      .withInput({
+        goodbye: false,
+        world: 'world',
+      })
+      .withMessage('booleans do not show the contents when false')
+      .toCompileTo('cruel world!');
+  });
+
+  it('zeros', function () {
+    expectTemplate('num1: {{num1}}, num2: {{num2}}')
+      .withInput({
+        num1: 42,
+        num2: 0,
+      })
+      .toCompileTo('num1: 42, num2: 0');
+
+    expectTemplate('num: {{.}}').withInput(0).toCompileTo('num: 0');
+
+    expectTemplate('num: {{num1/num2}}')
+      .withInput({ num1: { num2: 0 } })
+      .toCompileTo('num: 0');
+  });
+
+  it('false', function () {
+    /* eslint-disable no-new-wrappers */
+    expectTemplate('val1: {{val1}}, val2: {{val2}}')
+      .withInput({
+        val1: false,
+        val2: new Boolean(false),
+      })
+      .toCompileTo('val1: false, val2: false');
+
+    expectTemplate('val: {{.}}').withInput(false).toCompileTo('val: false');
+
+    expectTemplate('val: {{val1/val2}}')
+      .withInput({ val1: { val2: false } })
+      .toCompileTo('val: false');
+
+    expectTemplate('val1: {{{val1}}}, val2: {{{val2}}}')
+      .withInput({
+        val1: false,
+        val2: new Boolean(false),
+      })
+      .toCompileTo('val1: false, val2: false');
+
+    expectTemplate('val: {{{val1/val2}}}')
+      .withInput({ val1: { val2: false } })
+      .toCompileTo('val: false');
+    /* eslint-enable */
+  });
+
+  it('should handle undefined and null', function () {
+    expectTemplate('{{awesome undefined null}}')
+      .withInput({
+        awesome: function (_undefined, _null, options) {
+          return (
+            (_undefined === undefined) +
+            ' ' +
+            (_null === null) +
+            ' ' +
+            typeof options
+          );
+        },
+      })
+      .toCompileTo('true true object');
+
+    expectTemplate('{{undefined}}')
+      .withInput({
+        undefined: function () {
+          return 'undefined!';
+        },
+      })
+      .toCompileTo('undefined!');
+
+    expectTemplate('{{null}}')
+      .withInput({
+        null: function () {
+          return 'null!';
+        },
+      })
+      .toCompileTo('null!');
+  });
+
+  it('newlines', function () {
+    expectTemplate("Alan's\nTest").toCompileTo("Alan's\nTest");
+
+    expectTemplate("Alan's\rTest").toCompileTo("Alan's\rTest");
+  });
+
+  it('escaping text', function () {
+    expectTemplate("Awesome's")
+      .withMessage(
+        "text is escaped so that it doesn't get caught on single quotes"
+      )
+      .toCompileTo("Awesome's");
+
+    expectTemplate('Awesome\\')
+      .withMessage("text is escaped so that the closing quote can't be ignored")
+      .toCompileTo('Awesome\\');
+
+    expectTemplate('Awesome\\\\ foo')
+      .withMessage("text is escaped so that it doesn't mess up backslashes")
+      .toCompileTo('Awesome\\\\ foo');
+
+    expectTemplate('Awesome {{foo}}')
+      .withInput({ foo: '\\' })
+      .withMessage("text is escaped so that it doesn't mess up backslashes")
+      .toCompileTo('Awesome \\');
+
+    expectTemplate(" ' ' ")
+      .withMessage('double quotes never produce invalid javascript')
+      .toCompileTo(" ' ' ");
+  });
+
+  it('escaping expressions', function () {
+    expectTemplate('{{{awesome}}}')
+      .withInput({ awesome: "&'\\<>" })
+      .withMessage("expressions with 3 handlebars aren't escaped")
+      .toCompileTo("&'\\<>");
+
+    expectTemplate('{{&awesome}}')
+      .withInput({ awesome: "&'\\<>" })
+      .withMessage("expressions with {{& handlebars aren't escaped")
+      .toCompileTo("&'\\<>");
+
+    expectTemplate('{{awesome}}')
+      .withInput({ awesome: '&"\'`\\<>' })
+      .withMessage('by default expressions should be escaped')
+      .toCompileTo('&amp;&quot;&#x27;&#x60;\\&lt;&gt;');
+
+    expectTemplate('{{awesome}}')
+      .withInput({ awesome: 'Escaped, <b> looks like: &lt;b&gt;' })
+      .withMessage('escaping should properly handle amperstands')
+      .toCompileTo('Escaped, &lt;b&gt; looks like: &amp;lt;b&amp;gt;');
+  });
+
+  it("functions returning safestrings shouldn't be escaped", function () {
+    expectTemplate('{{awesome}}')
+      .withInput({
+        awesome: function () {
+          return new Handlebars.SafeString("&'\\<>");
+        },
+      })
+      .withMessage("functions returning safestrings aren't escaped")
+      .toCompileTo("&'\\<>");
+  });
+
+  it('functions', function () {
+    expectTemplate('{{awesome}}')
+      .withInput({
+        awesome: function () {
+          return 'Awesome';
+        },
+      })
+      .withMessage('functions are called and render their output')
+      .toCompileTo('Awesome');
+
+    expectTemplate('{{awesome}}')
+      .withInput({
+        awesome: function () {
+          return this.more;
+        },
+        more: 'More awesome',
+      })
+      .withMessage('functions are bound to the context')
+      .toCompileTo('More awesome');
+  });
+
+  it('functions with context argument', function () {
+    expectTemplate('{{awesome frank}}')
+      .withInput({
+        awesome: function (context) {
+          return context;
+        },
+        frank: 'Frank',
+      })
+      .withMessage('functions are called with context arguments')
+      .toCompileTo('Frank');
+  });
+
+  it('pathed functions with context argument', function () {
+    expectTemplate('{{bar.awesome frank}}')
+      .withInput({
+        bar: {
+          awesome: function (context) {
+            return context;
+          },
+        },
+        frank: 'Frank',
+      })
+      .withMessage('functions are called with context arguments')
+      .toCompileTo('Frank');
+  });
+
+  it('depthed functions with context argument', function () {
+    expectTemplate('{{#with frank}}{{../awesome .}}{{/with}}')
+      .withInput({
+        awesome: function (context) {
+          return context;
+        },
+        frank: 'Frank',
+      })
+      .withMessage('functions are called with context arguments')
+      .toCompileTo('Frank');
+  });
+
+  it('block functions with context argument', function () {
+    expectTemplate('{{#awesome 1}}inner {{.}}{{/awesome}}')
+      .withInput({
+        awesome: function (context, options) {
+          return options.fn(context);
+        },
+      })
+      .withMessage('block functions are called with context and options')
+      .toCompileTo('inner 1');
+  });
+
+  it('depthed block functions with context argument', function () {
+    expectTemplate(
+      '{{#with value}}{{#../awesome 1}}inner {{.}}{{/../awesome}}{{/with}}'
+    )
+      .withInput({
+        value: true,
+        awesome: function (context, options) {
+          return options.fn(context);
+        },
+      })
+      .withMessage('block functions are called with context and options')
+      .toCompileTo('inner 1');
+  });
+
+  it('block functions without context argument', function () {
+    expectTemplate('{{#awesome}}inner{{/awesome}}')
+      .withInput({
+        awesome: function (options) {
+          return options.fn(this);
+        },
+      })
+      .withMessage('block functions are called with options')
+      .toCompileTo('inner');
+  });
+
+  it('pathed block functions without context argument', function () {
+    expectTemplate('{{#foo.awesome}}inner{{/foo.awesome}}')
+      .withInput({
+        foo: {
+          awesome: function () {
+            return this;
+          },
+        },
+      })
+      .withMessage('block functions are called with options')
+      .toCompileTo('inner');
+  });
+
+  it('depthed block functions without context argument', function () {
+    expectTemplate(
+      '{{#with value}}{{#../awesome}}inner{{/../awesome}}{{/with}}'
+    )
+      .withInput({
+        value: true,
+        awesome: function () {
+          return this;
+        },
+      })
+      .withMessage('block functions are called with options')
+      .toCompileTo('inner');
+  });
+
+  it('paths with hyphens', function () {
+    expectTemplate('{{foo-bar}}')
+      .withInput({ 'foo-bar': 'baz' })
+      .withMessage('Paths can contain hyphens (-)')
+      .toCompileTo('baz');
+
+    expectTemplate('{{foo.foo-bar}}')
+      .withInput({ foo: { 'foo-bar': 'baz' } })
+      .withMessage('Paths can contain hyphens (-)')
+      .toCompileTo('baz');
+
+    expectTemplate('{{foo/foo-bar}}')
+      .withInput({ foo: { 'foo-bar': 'baz' } })
+      .withMessage('Paths can contain hyphens (-)')
+      .toCompileTo('baz');
+  });
+
+  it('nested paths', function () {
+    expectTemplate('Goodbye {{alan/expression}} world!')
+      .withInput({ alan: { expression: 'beautiful' } })
+      .withMessage('Nested paths access nested objects')
+      .toCompileTo('Goodbye beautiful world!');
+  });
+
+  it('nested paths with Map', function () {
+    expectTemplate('Goodbye {{alan/expression}} world!')
+      .withInput({ alan: new Map([['expression', 'beautiful']]) })
+      .withMessage('Nested paths access nested objects')
+      .toCompileTo('Goodbye beautiful world!');
+  });
+
+  it('nested paths with empty string value', function () {
+    expectTemplate('Goodbye {{alan/expression}} world!')
+      .withInput({ alan: { expression: '' } })
+      .withMessage('Nested paths access nested objects with empty string')
+      .toCompileTo('Goodbye  world!');
+  });
+
+  it('literal paths', function () {
+    expectTemplate('Goodbye {{[@alan]/expression}} world!')
+      .withInput({ '@alan': { expression: 'beautiful' } })
+      .withMessage('Literal paths can be used')
+      .toCompileTo('Goodbye beautiful world!');
+
+    expectTemplate('Goodbye {{[foo bar]/expression}} world!')
+      .withInput({ 'foo bar': { expression: 'beautiful' } })
+      .withMessage('Literal paths can be used')
+      .toCompileTo('Goodbye beautiful world!');
+  });
+
+  it('literal references', function () {
+    expectTemplate('Goodbye {{[foo bar]}} world!')
+      .withInput({ 'foo bar': 'beautiful' })
+      .toCompileTo('Goodbye beautiful world!');
+
+    expectTemplate('Goodbye {{"foo bar"}} world!')
+      .withInput({ 'foo bar': 'beautiful' })
+      .toCompileTo('Goodbye beautiful world!');
+
+    expectTemplate("Goodbye {{'foo bar'}} world!")
+      .withInput({ 'foo bar': 'beautiful' })
+      .toCompileTo('Goodbye beautiful world!');
+
+    expectTemplate('Goodbye {{"foo[bar"}} world!')
+      .withInput({ 'foo[bar': 'beautiful' })
+      .toCompileTo('Goodbye beautiful world!');
+
+    expectTemplate('Goodbye {{"foo\'bar"}} world!')
+      .withInput({ "foo'bar": 'beautiful' })
+      .toCompileTo('Goodbye beautiful world!');
+
+    expectTemplate("Goodbye {{'foo\"bar'}} world!")
+      .withInput({ 'foo"bar': 'beautiful' })
+      .toCompileTo('Goodbye beautiful world!');
+  });
+
+  it("that current context path ({{.}}) doesn't hit helpers", function () {
+    expectTemplate('test: {{.}}')
+      .withInput(null)
+      .withHelpers({ helper: 'awesome' })
+      .toCompileTo('test: ');
+  });
+
+  it('complex but empty paths', function () {
+    expectTemplate('{{person/name}}')
+      .withInput({ person: { name: null } })
+      .toCompileTo('');
+
+    expectTemplate('{{person/name}}').withInput({ person: {} }).toCompileTo('');
+  });
+
+  it('this keyword in paths', function () {
+    expectTemplate('{{#goodbyes}}{{this}}{{/goodbyes}}')
+      .withInput({ goodbyes: ['goodbye', 'Goodbye', 'GOODBYE'] })
+      .withMessage('This keyword in paths evaluates to current context')
+      .toCompileTo('goodbyeGoodbyeGOODBYE');
+
+    expectTemplate('{{#hellos}}{{this/text}}{{/hellos}}')
+      .withInput({
+        hellos: [{ text: 'hello' }, { text: 'Hello' }, { text: 'HELLO' }],
+      })
+      .withMessage('This keyword evaluates in more complex paths')
+      .toCompileTo('helloHelloHELLO');
+  });
+
+  it('this keyword nested inside path', function () {
+    expectTemplate('{{#hellos}}{{text/this/foo}}{{/hellos}}').toThrow(
+      Error,
+      'Invalid path: text/this - 1:13'
+    );
+
+    expectTemplate('{{[this]}}').withInput({ this: 'bar' }).toCompileTo('bar');
+
+    expectTemplate('{{text/[this]}}')
+      .withInput({ text: { this: 'bar' } })
+      .toCompileTo('bar');
+  });
+
+  it('this keyword in helpers', function () {
+    var helpers = {
+      foo: function (value) {
+        return 'bar ' + value;
+      },
+    };
+
+    expectTemplate('{{#goodbyes}}{{foo this}}{{/goodbyes}}')
+      .withInput({ goodbyes: ['goodbye', 'Goodbye', 'GOODBYE'] })
+      .withHelpers(helpers)
+      .withMessage('This keyword in paths evaluates to current context')
+      .toCompileTo('bar goodbyebar Goodbyebar GOODBYE');
+
+    expectTemplate('{{#hellos}}{{foo this/text}}{{/hellos}}')
+      .withInput({
+        hellos: [{ text: 'hello' }, { text: 'Hello' }, { text: 'HELLO' }],
+      })
+      .withHelpers(helpers)
+      .withMessage('This keyword evaluates in more complex paths')
+      .toCompileTo('bar hellobar Hellobar HELLO');
+  });
+
+  it('this keyword nested inside helpers param', function () {
+    expectTemplate('{{#hellos}}{{foo text/this/foo}}{{/hellos}}').toThrow(
+      Error,
+      'Invalid path: text/this - 1:17'
+    );
+
+    expectTemplate('{{foo [this]}}')
+      .withInput({
+        foo: function (value) {
+          return value;
+        },
+        this: 'bar',
+      })
+      .toCompileTo('bar');
+
+    expectTemplate('{{foo text/[this]}}')
+      .withInput({
+        foo: function (value) {
+          return value;
+        },
+        text: { this: 'bar' },
+      })
+      .toCompileTo('bar');
+  });
+
+  it('pass string literals', function () {
+    expectTemplate('{{"foo"}}').toCompileTo('');
+
+    expectTemplate('{{"foo"}}').withInput({ foo: 'bar' }).toCompileTo('bar');
+
+    expectTemplate('{{#"foo"}}{{.}}{{/"foo"}}')
+      .withInput({
+        foo: ['bar', 'baz'],
+      })
+      .toCompileTo('barbaz');
+  });
+
+  it('pass number literals', function () {
+    expectTemplate('{{12}}').toCompileTo('');
+
+    expectTemplate('{{12}}').withInput({ 12: 'bar' }).toCompileTo('bar');
+
+    expectTemplate('{{12.34}}').toCompileTo('');
+
+    expectTemplate('{{12.34}}').withInput({ 12.34: 'bar' }).toCompileTo('bar');
+
+    expectTemplate('{{12.34 1}}')
+      .withInput({
+        12.34: function (arg) {
+          return 'bar' + arg;
+        },
+      })
+      .toCompileTo('bar1');
+  });
+
+  it('pass boolean literals', function () {
+    expectTemplate('{{true}}').toCompileTo('');
+
+    expectTemplate('{{true}}').withInput({ '': 'foo' }).toCompileTo('');
+
+    expectTemplate('{{false}}').withInput({ false: 'foo' }).toCompileTo('foo');
+  });
+
+  it('should handle literals in subexpression', function () {
+    expectTemplate('{{foo (false)}}')
+      .withInput({
+        false: function () {
+          return 'bar';
+        },
+      })
+      .withHelper('foo', function (arg) {
+        return arg;
+      })
+      .toCompileTo('bar');
+  });
+});

spec/blocks.js

@@ -0,0 +1,452 @@
+describe('blocks', function () {
+  it('array', function () {
+    var string = '{{#goodbyes}}{{text}}! {{/goodbyes}}cruel {{world}}!';
+
+    expectTemplate(string)
+      .withInput({
+        goodbyes: [
+          { text: 'goodbye' },
+          { text: 'Goodbye' },
+          { text: 'GOODBYE' },
+        ],
+        world: 'world',
+      })
+      .withMessage('Arrays iterate over the contents when not empty')
+      .toCompileTo('goodbye! Goodbye! GOODBYE! cruel world!');
+
+    expectTemplate(string)
+      .withInput({
+        goodbyes: [],
+        world: 'world',
+      })
+      .withMessage('Arrays ignore the contents when empty')
+      .toCompileTo('cruel world!');
+  });
+
+  it('array without data', function () {
+    expectTemplate(
+      '{{#goodbyes}}{{text}}{{/goodbyes}} {{#goodbyes}}{{text}}{{/goodbyes}}'
+    )
+      .withInput({
+        goodbyes: [
+          { text: 'goodbye' },
+          { text: 'Goodbye' },
+          { text: 'GOODBYE' },
+        ],
+        world: 'world',
+      })
+      .withCompileOptions({ compat: false })
+      .toCompileTo('goodbyeGoodbyeGOODBYE goodbyeGoodbyeGOODBYE');
+  });
+
+  it('array with @index', function () {
+    expectTemplate(
+      '{{#goodbyes}}{{@index}}. {{text}}! {{/goodbyes}}cruel {{world}}!'
+    )
+      .withInput({
+        goodbyes: [
+          { text: 'goodbye' },
+          { text: 'Goodbye' },
+          { text: 'GOODBYE' },
+        ],
+        world: 'world',
+      })
+      .withMessage('The @index variable is used')
+      .toCompileTo('0. goodbye! 1. Goodbye! 2. GOODBYE! cruel world!');
+  });
+
+  it('empty block', function () {
+    var string = '{{#goodbyes}}{{/goodbyes}}cruel {{world}}!';
+
+    expectTemplate(string)
+      .withInput({
+        goodbyes: [
+          { text: 'goodbye' },
+          { text: 'Goodbye' },
+          { text: 'GOODBYE' },
+        ],
+        world: 'world',
+      })
+      .withMessage('Arrays iterate over the contents when not empty')
+      .toCompileTo('cruel world!');
+
+    expectTemplate(string)
+      .withInput({
+        goodbyes: [],
+        world: 'world',
+      })
+      .withMessage('Arrays ignore the contents when empty')
+      .toCompileTo('cruel world!');
+  });
+
+  it('block with complex lookup', function () {
+    expectTemplate('{{#goodbyes}}{{text}} cruel {{../name}}! {{/goodbyes}}')
+      .withInput({
+        name: 'Alan',
+        goodbyes: [
+          { text: 'goodbye' },
+          { text: 'Goodbye' },
+          { text: 'GOODBYE' },
+        ],
+      })
+      .withMessage(
+        'Templates can access variables in contexts up the stack with relative path syntax'
+      )
+      .toCompileTo(
+        'goodbye cruel Alan! Goodbye cruel Alan! GOODBYE cruel Alan! '
+      );
+  });
+
+  it('multiple blocks with complex lookup', function () {
+    expectTemplate('{{#goodbyes}}{{../name}}{{../name}}{{/goodbyes}}')
+      .withInput({
+        name: 'Alan',
+        goodbyes: [
+          { text: 'goodbye' },
+          { text: 'Goodbye' },
+          { text: 'GOODBYE' },
+        ],
+      })
+      .toCompileTo('AlanAlanAlanAlanAlanAlan');
+  });
+
+  it('block with complex lookup using nested context', function () {
+    expectTemplate(
+      '{{#goodbyes}}{{text}} cruel {{foo/../name}}! {{/goodbyes}}'
+    ).toThrow(Error);
+  });
+
+  it('block with deep nested complex lookup', function () {
+    expectTemplate(
+      '{{#outer}}Goodbye {{#inner}}cruel {{../sibling}} {{../../omg}}{{/inner}}{{/outer}}'
+    )
+      .withInput({
+        omg: 'OMG!',
+        outer: [{ sibling: 'sad', inner: [{ text: 'goodbye' }] }],
+      })
+      .toCompileTo('Goodbye cruel sad OMG!');
+  });
+
+  it('works with cached blocks', function () {
+    expectTemplate(
+      '{{#each person}}{{#with .}}{{first}} {{last}}{{/with}}{{/each}}'
+    )
+      .withCompileOptions({ data: false })
+      .withInput({
+        person: [
+          { first: 'Alan', last: 'Johnson' },
+          { first: 'Alan', last: 'Johnson' },
+        ],
+      })
+      .toCompileTo('Alan JohnsonAlan Johnson');
+  });
+
+  describe('inverted sections', function () {
+    it('inverted sections with unset value', function () {
+      expectTemplate(
+        '{{#goodbyes}}{{this}}{{/goodbyes}}{{^goodbyes}}Right On!{{/goodbyes}}'
+      )
+        .withMessage("Inverted section rendered when value isn't set.")
+        .toCompileTo('Right On!');
+    });
+
+    it('inverted section with false value', function () {
+      expectTemplate(
+        '{{#goodbyes}}{{this}}{{/goodbyes}}{{^goodbyes}}Right On!{{/goodbyes}}'
+      )
+        .withInput({ goodbyes: false })
+        .withMessage('Inverted section rendered when value is false.')
+        .toCompileTo('Right On!');
+    });
+
+    it('inverted section with empty set', function () {
+      expectTemplate(
+        '{{#goodbyes}}{{this}}{{/goodbyes}}{{^goodbyes}}Right On!{{/goodbyes}}'
+      )
+        .withInput({ goodbyes: [] })
+        .withMessage('Inverted section rendered when value is empty set.')
+        .toCompileTo('Right On!');
+    });
+
+    it('block inverted sections', function () {
+      expectTemplate('{{#people}}{{name}}{{^}}{{none}}{{/people}}')
+        .withInput({ none: 'No people' })
+        .toCompileTo('No people');
+    });
+
+    it('chained inverted sections', function () {
+      expectTemplate('{{#people}}{{name}}{{else if none}}{{none}}{{/people}}')
+        .withInput({ none: 'No people' })
+        .toCompileTo('No people');
+
+      expectTemplate(
+        '{{#people}}{{name}}{{else if nothere}}fail{{else unless nothere}}{{none}}{{/people}}'
+      )
+        .withInput({ none: 'No people' })
+        .toCompileTo('No people');
+
+      expectTemplate(
+        '{{#people}}{{name}}{{else if none}}{{none}}{{else}}fail{{/people}}'
+      )
+        .withInput({ none: 'No people' })
+        .toCompileTo('No people');
+    });
+
+    it('chained inverted sections with mismatch', function () {
+      expectTemplate(
+        '{{#people}}{{name}}{{else if none}}{{none}}{{/if}}'
+      ).toThrow(Error);
+    });
+
+    it('block inverted sections with empty arrays', function () {
+      expectTemplate('{{#people}}{{name}}{{^}}{{none}}{{/people}}')
+        .withInput({
+          none: 'No people',
+          people: [],
+        })
+        .toCompileTo('No people');
+    });
+  });
+
+  describe('standalone sections', function () {
+    it('block standalone else sections', function () {
+      expectTemplate('{{#people}}\n{{name}}\n{{^}}\n{{none}}\n{{/people}}\n')
+        .withInput({ none: 'No people' })
+        .toCompileTo('No people\n');
+
+      expectTemplate('{{#none}}\n{{.}}\n{{^}}\n{{none}}\n{{/none}}\n')
+        .withInput({ none: 'No people' })
+        .toCompileTo('No people\n');
+
+      expectTemplate('{{#people}}\n{{name}}\n{{^}}\n{{none}}\n{{/people}}\n')
+        .withInput({ none: 'No people' })
+        .toCompileTo('No people\n');
+    });
+
+    it('block standalone else sections can be disabled', function () {
+      expectTemplate('{{#people}}\n{{name}}\n{{^}}\n{{none}}\n{{/people}}\n')
+        .withInput({ none: 'No people' })
+        .withCompileOptions({ ignoreStandalone: true })
+        .toCompileTo('\nNo people\n\n');
+
+      expectTemplate('{{#none}}\n{{.}}\n{{^}}\nFail\n{{/none}}\n')
+        .withInput({ none: 'No people' })
+        .withCompileOptions({ ignoreStandalone: true })
+        .toCompileTo('\nNo people\n\n');
+    });
+
+    it('block standalone chained else sections', function () {
+      expectTemplate(
+        '{{#people}}\n{{name}}\n{{else if none}}\n{{none}}\n{{/people}}\n'
+      )
+        .withInput({ none: 'No people' })
+        .toCompileTo('No people\n');
+
+      expectTemplate(
+        '{{#people}}\n{{name}}\n{{else if none}}\n{{none}}\n{{^}}\n{{/people}}\n'
+      )
+        .withInput({ none: 'No people' })
+        .toCompileTo('No people\n');
+    });
+
+    it('should handle nesting', function () {
+      expectTemplate('{{#data}}\n{{#if true}}\n{{.}}\n{{/if}}\n{{/data}}\nOK.')
+        .withInput({
+          data: [1, 3, 5],
+        })
+        .toCompileTo('1\n3\n5\nOK.');
+    });
+  });
+
+  describe('compat mode', function () {
+    it('block with deep recursive lookup lookup', function () {
+      expectTemplate(
+        '{{#outer}}Goodbye {{#inner}}cruel {{omg}}{{/inner}}{{/outer}}'
+      )
+        .withInput({ omg: 'OMG!', outer: [{ inner: [{ text: 'goodbye' }] }] })
+        .withCompileOptions({ compat: true })
+        .toCompileTo('Goodbye cruel OMG!');
+    });
+
+    it('block with deep recursive pathed lookup', function () {
+      expectTemplate(
+        '{{#outer}}Goodbye {{#inner}}cruel {{omg.yes}}{{/inner}}{{/outer}}'
+      )
+        .withInput({
+          omg: { yes: 'OMG!' },
+          outer: [{ inner: [{ yes: 'no', text: 'goodbye' }] }],
+        })
+        .withCompileOptions({ compat: true })
+        .toCompileTo('Goodbye cruel OMG!');
+    });
+
+    it('block with missed recursive lookup', function () {
+      expectTemplate(
+        '{{#outer}}Goodbye {{#inner}}cruel {{omg.yes}}{{/inner}}{{/outer}}'
+      )
+        .withInput({
+          omg: { no: 'OMG!' },
+          outer: [{ inner: [{ yes: 'no', text: 'goodbye' }] }],
+        })
+        .withCompileOptions({ compat: true })
+        .toCompileTo('Goodbye cruel ');
+    });
+  });
+
+  describe('decorators', function () {
+    it('should apply mustache decorators', function () {
+      expectTemplate('{{#helper}}{{*decorator}}{{/helper}}')
+        .withHelper('helper', function (options) {
+          return options.fn.run;
+        })
+        .withDecorator('decorator', function (fn) {
+          fn.run = 'success';
+          return fn;
+        })
+        .toCompileTo('success');
+    });
+
+    it('should apply allow undefined return', function () {
+      expectTemplate('{{#helper}}{{*decorator}}suc{{/helper}}')
+        .withHelper('helper', function (options) {
+          return options.fn() + options.fn.run;
+        })
+        .withDecorator('decorator', function (fn) {
+          fn.run = 'cess';
+        })
+        .toCompileTo('success');
+    });
+
+    it('should apply block decorators', function () {
+      expectTemplate(
+        '{{#helper}}{{#*decorator}}success{{/decorator}}{{/helper}}'
+      )
+        .withHelper('helper', function (options) {
+          return options.fn.run;
+        })
+        .withDecorator('decorator', function (fn, props, container, options) {
+          fn.run = options.fn();
+          return fn;
+        })
+        .toCompileTo('success');
+    });
+
+    it('should support nested decorators', function () {
+      expectTemplate(
+        '{{#helper}}{{#*decorator}}{{#*nested}}suc{{/nested}}cess{{/decorator}}{{/helper}}'
+      )
+        .withHelper('helper', function (options) {
+          return options.fn.run;
+        })
+        .withDecorators({
+          decorator: function (fn, props, container, options) {
+            fn.run = options.fn.nested + options.fn();
+            return fn;
+          },
+          nested: function (fn, props, container, options) {
+            props.nested = options.fn();
+          },
+        })
+        .toCompileTo('success');
+    });
+
+    it('should apply multiple decorators', function () {
+      expectTemplate(
+        '{{#helper}}{{#*decorator}}suc{{/decorator}}{{#*decorator}}cess{{/decorator}}{{/helper}}'
+      )
+        .withHelper('helper', function (options) {
+          return options.fn.run;
+        })
+        .withDecorator('decorator', function (fn, props, container, options) {
+          fn.run = (fn.run || '') + options.fn();
+          return fn;
+        })
+        .toCompileTo('success');
+    });
+
+    it('should access parent variables', function () {
+      expectTemplate('{{#helper}}{{*decorator foo}}{{/helper}}')
+        .withHelper('helper', function (options) {
+          return options.fn.run;
+        })
+        .withDecorator('decorator', function (fn, props, container, options) {
+          fn.run = options.args;
+          return fn;
+        })
+        .withInput({ foo: 'success' })
+        .toCompileTo('success');
+    });
+
+    it('should work with root program', function () {
+      var run;
+      expectTemplate('{{*decorator "success"}}')
+        .withDecorator('decorator', function (fn, props, container, options) {
+          expect(options.args[0]).toBe('success');
+          run = true;
+          return fn;
+        })
+        .withInput({ foo: 'success' })
+        .toCompileTo('');
+      expect(run).toBe(true);
+    });
+
+    it('should fail when accessing variables from root', function () {
+      var run;
+      expectTemplate('{{*decorator foo}}')
+        .withDecorator('decorator', function (fn, props, container, options) {
+          expect(options.args[0]).toBeUndefined();
+          run = true;
+          return fn;
+        })
+        .withInput({ foo: 'fail' })
+        .toCompileTo('');
+      expect(run).toBe(true);
+    });
+
+    describe('registration', function () {
+      it('unregisters', function () {
+        handlebarsEnv.decorators = {};
+
+        handlebarsEnv.registerDecorator('foo', function () {
+          return 'fail';
+        });
+
+        expect(handlebarsEnv.decorators.foo).toBeTruthy();
+        handlebarsEnv.unregisterDecorator('foo');
+        expect(handlebarsEnv.decorators.foo).toBeUndefined();
+      });
+
+      it('allows multiple globals', function () {
+        handlebarsEnv.decorators = {};
+
+        handlebarsEnv.registerDecorator({
+          foo: function () {},
+          bar: function () {},
+        });
+
+        expect(handlebarsEnv.decorators.foo).toBeTruthy();
+        expect(handlebarsEnv.decorators.bar).toBeTruthy();
+        handlebarsEnv.unregisterDecorator('foo');
+        handlebarsEnv.unregisterDecorator('bar');
+        expect(handlebarsEnv.decorators.foo).toBeUndefined();
+        expect(handlebarsEnv.decorators.bar).toBeUndefined();
+      });
+
+      it('fails with multiple and args', function () {
+        expect(function () {
+          handlebarsEnv.registerDecorator(
+            {
+              world: function () {
+                return 'world!';
+              },
+              testHelper: function () {
+                return 'found it!';
+              },
+            },
+            {}
+          );
+        }).toThrow('Arg not supported with multiple decorators');
+      });
+    });
+  });
+});

spec/builtins.js

@@ -0,0 +1,808 @@
+describe('builtin helpers', function () {
+  describe('#if', function () {
+    it('if', function () {
+      var string = '{{#if goodbye}}GOODBYE {{/if}}cruel {{world}}!';
+
+      expectTemplate(string)
+        .withInput({
+          goodbye: true,
+          world: 'world',
+        })
+        .withMessage('if with boolean argument shows the contents when true')
+        .toCompileTo('GOODBYE cruel world!');
+
+      expectTemplate(string)
+        .withInput({
+          goodbye: 'dummy',
+          world: 'world',
+        })
+        .withMessage('if with string argument shows the contents')
+        .toCompileTo('GOODBYE cruel world!');
+
+      expectTemplate(string)
+        .withInput({
+          goodbye: false,
+          world: 'world',
+        })
+        .withMessage(
+          'if with boolean argument does not show the contents when false'
+        )
+        .toCompileTo('cruel world!');
+
+      expectTemplate(string)
+        .withInput({ world: 'world' })
+        .withMessage('if with undefined does not show the contents')
+        .toCompileTo('cruel world!');
+
+      expectTemplate(string)
+        .withInput({
+          goodbye: ['foo'],
+          world: 'world',
+        })
+        .withMessage('if with non-empty array shows the contents')
+        .toCompileTo('GOODBYE cruel world!');
+
+      expectTemplate(string)
+        .withInput({
+          goodbye: [],
+          world: 'world',
+        })
+        .withMessage('if with empty array does not show the contents')
+        .toCompileTo('cruel world!');
+
+      expectTemplate(string)
+        .withInput({
+          goodbye: 0,
+          world: 'world',
+        })
+        .withMessage('if with zero does not show the contents')
+        .toCompileTo('cruel world!');
+
+      expectTemplate(
+        '{{#if goodbye includeZero=true}}GOODBYE {{/if}}cruel {{world}}!'
+      )
+        .withInput({
+          goodbye: 0,
+          world: 'world',
+        })
+        .withMessage('if with zero does not show the contents')
+        .toCompileTo('GOODBYE cruel world!');
+    });
+
+    it('if with function argument', function () {
+      var string = '{{#if goodbye}}GOODBYE {{/if}}cruel {{world}}!';
+
+      expectTemplate(string)
+        .withInput({
+          goodbye: function () {
+            return true;
+          },
+          world: 'world',
+        })
+        .withMessage(
+          'if with function shows the contents when function returns true'
+        )
+        .toCompileTo('GOODBYE cruel world!');
+
+      expectTemplate(string)
+        .withInput({
+          goodbye: function () {
+            return this.world;
+          },
+          world: 'world',
+        })
+        .withMessage(
+          'if with function shows the contents when function returns string'
+        )
+        .toCompileTo('GOODBYE cruel world!');
+
+      expectTemplate(string)
+        .withInput({
+          goodbye: function () {
+            return false;
+          },
+          world: 'world',
+        })
+        .withMessage(
+          'if with function does not show the contents when returns false'
+        )
+        .toCompileTo('cruel world!');
+
+      expectTemplate(string)
+        .withInput({
+          goodbye: function () {
+            return this.foo;
+          },
+          world: 'world',
+        })
+        .withMessage(
+          'if with function does not show the contents when returns undefined'
+        )
+        .toCompileTo('cruel world!');
+    });
+
+    it('should not change the depth list', function () {
+      expectTemplate(
+        '{{#with foo}}{{#if goodbye}}GOODBYE cruel {{../world}}!{{/if}}{{/with}}'
+      )
+        .withInput({
+          foo: { goodbye: true },
+          world: 'world',
+        })
+        .toCompileTo('GOODBYE cruel world!');
+    });
+  });
+
+  describe('#with', function () {
+    it('with', function () {
+      expectTemplate('{{#with person}}{{first}} {{last}}{{/with}}')
+        .withInput({
+          person: {
+            first: 'Alan',
+            last: 'Johnson',
+          },
+        })
+        .toCompileTo('Alan Johnson');
+    });
+
+    it('with with function argument', function () {
+      expectTemplate('{{#with person}}{{first}} {{last}}{{/with}}')
+        .withInput({
+          person: function () {
+            return {
+              first: 'Alan',
+              last: 'Johnson',
+            };
+          },
+        })
+        .toCompileTo('Alan Johnson');
+    });
+
+    it('with with else', function () {
+      expectTemplate(
+        '{{#with person}}Person is present{{else}}Person is not present{{/with}}'
+      ).toCompileTo('Person is not present');
+    });
+
+    it('with provides block parameter', function () {
+      expectTemplate('{{#with person as |foo|}}{{foo.first}} {{last}}{{/with}}')
+        .withInput({
+          person: {
+            first: 'Alan',
+            last: 'Johnson',
+          },
+        })
+        .toCompileTo('Alan Johnson');
+    });
+
+    it('works when data is disabled', function () {
+      expectTemplate('{{#with person as |foo|}}{{foo.first}} {{last}}{{/with}}')
+        .withInput({ person: { first: 'Alan', last: 'Johnson' } })
+        .withCompileOptions({ data: false })
+        .toCompileTo('Alan Johnson');
+    });
+  });
+
+  describe('#each', function () {
+    beforeEach(function () {
+      handlebarsEnv.registerHelper('detectDataInsideEach', function (options) {
+        return options.data && options.data.exclaim;
+      });
+    });
+
+    it('each', function () {
+      var string = '{{#each goodbyes}}{{text}}! {{/each}}cruel {{world}}!';
+
+      expectTemplate(string)
+        .withInput({
+          goodbyes: [
+            { text: 'goodbye' },
+            { text: 'Goodbye' },
+            { text: 'GOODBYE' },
+          ],
+          world: 'world',
+        })
+        .withMessage(
+          'each with array argument iterates over the contents when not empty'
+        )
+        .toCompileTo('goodbye! Goodbye! GOODBYE! cruel world!');
+
+      expectTemplate(string)
+        .withInput({
+          goodbyes: [],
+          world: 'world',
+        })
+        .withMessage('each with array argument ignores the contents when empty')
+        .toCompileTo('cruel world!');
+    });
+
+    it('each without data', function () {
+      expectTemplate('{{#each goodbyes}}{{text}}! {{/each}}cruel {{world}}!')
+        .withInput({
+          goodbyes: [
+            { text: 'goodbye' },
+            { text: 'Goodbye' },
+            { text: 'GOODBYE' },
+          ],
+          world: 'world',
+        })
+        .withRuntimeOptions({ data: false })
+        .withCompileOptions({ data: false })
+        .toCompileTo('goodbye! Goodbye! GOODBYE! cruel world!');
+
+      expectTemplate('{{#each .}}{{.}}{{/each}}')
+        .withInput({ goodbyes: 'cruel', world: 'world' })
+        .withRuntimeOptions({ data: false })
+        .withCompileOptions({ data: false })
+        .toCompileTo('cruelworld');
+    });
+
+    it('each without context', function () {
+      expectTemplate('{{#each goodbyes}}{{text}}! {{/each}}cruel {{world}}!')
+        .withInput(undefined)
+        .toCompileTo('cruel !');
+    });
+
+    it('each with an object and @key', function () {
+      var string =
+        '{{#each goodbyes}}{{@key}}. {{text}}! {{/each}}cruel {{world}}!';
+
+      function Clazz() {
+        this['<b>#1</b>'] = { text: 'goodbye' };
+        this[2] = { text: 'GOODBYE' };
+      }
+      Clazz.prototype.foo = 'fail';
+      var hash = { goodbyes: new Clazz(), world: 'world' };
+
+      // Object property iteration order is undefined according to ECMA spec,
+      // so we need to check both possible orders
+      // @see http://stackoverflow.com/questions/280713/elements-order-in-a-for-in-loop
+      var actual = CompilerContext.compile(string)(hash);
+      var expected1 =
+        '&lt;b&gt;#1&lt;/b&gt;. goodbye! 2. GOODBYE! cruel world!';
+      var expected2 =
+        '2. GOODBYE! &lt;b&gt;#1&lt;/b&gt;. goodbye! cruel world!';
+
+      expect([expected1, expected2]).toContain(actual);
+
+      expectTemplate(string)
+        .withInput({
+          goodbyes: {},
+          world: 'world',
+        })
+        .toCompileTo('cruel world!');
+    });
+
+    it('each with @index', function () {
+      expectTemplate(
+        '{{#each goodbyes}}{{@index}}. {{text}}! {{/each}}cruel {{world}}!'
+      )
+        .withInput({
+          goodbyes: [
+            { text: 'goodbye' },
+            { text: 'Goodbye' },
+            { text: 'GOODBYE' },
+          ],
+          world: 'world',
+        })
+        .withMessage('The @index variable is used')
+        .toCompileTo('0. goodbye! 1. Goodbye! 2. GOODBYE! cruel world!');
+    });
+
+    it('each with nested @index', function () {
+      expectTemplate(
+        '{{#each goodbyes}}{{@index}}. {{text}}! {{#each ../goodbyes}}{{@index}} {{/each}}After {{@index}} {{/each}}{{@index}}cruel {{world}}!'
+      )
+        .withInput({
+          goodbyes: [
+            { text: 'goodbye' },
+            { text: 'Goodbye' },
+            { text: 'GOODBYE' },
+          ],
+          world: 'world',
+        })
+        .withMessage('The @index variable is used')
+        .toCompileTo(
+          '0. goodbye! 0 1 2 After 0 1. Goodbye! 0 1 2 After 1 2. GOODBYE! 0 1 2 After 2 cruel world!'
+        );
+    });
+
+    it('each with block params', function () {
+      expectTemplate(
+        '{{#each goodbyes as |value index|}}{{index}}. {{value.text}}! {{#each ../goodbyes as |childValue childIndex|}} {{index}} {{childIndex}}{{/each}} After {{index}} {{/each}}{{index}}cruel {{world}}!'
+      )
+        .withInput({
+          goodbyes: [{ text: 'goodbye' }, { text: 'Goodbye' }],
+          world: 'world',
+        })
+        .toCompileTo(
+          '0. goodbye!  0 0 0 1 After 0 1. Goodbye!  1 0 1 1 After 1 cruel world!'
+        );
+    });
+
+    it('each with block params and strict compilation', function () {
+      expectTemplate(
+        '{{#each goodbyes as |value index|}}{{index}}. {{value.text}}!{{/each}}'
+      )
+        .withCompileOptions({ strict: true })
+        .withInput({ goodbyes: [{ text: 'goodbye' }, { text: 'Goodbye' }] })
+        .toCompileTo('0. goodbye!1. Goodbye!');
+    });
+
+    it('each object with @index', function () {
+      expectTemplate(
+        '{{#each goodbyes}}{{@index}}. {{text}}! {{/each}}cruel {{world}}!'
+      )
+        .withInput({
+          goodbyes: {
+            a: { text: 'goodbye' },
+            b: { text: 'Goodbye' },
+            c: { text: 'GOODBYE' },
+          },
+          world: 'world',
+        })
+        .withMessage('The @index variable is used')
+        .toCompileTo('0. goodbye! 1. Goodbye! 2. GOODBYE! cruel world!');
+    });
+
+    it('each with @first', function () {
+      expectTemplate(
+        '{{#each goodbyes}}{{#if @first}}{{text}}! {{/if}}{{/each}}cruel {{world}}!'
+      )
+        .withInput({
+          goodbyes: [
+            { text: 'goodbye' },
+            { text: 'Goodbye' },
+            { text: 'GOODBYE' },
+          ],
+          world: 'world',
+        })
+        .withMessage('The @first variable is used')
+        .toCompileTo('goodbye! cruel world!');
+    });
+
+    it('each with nested @first', function () {
+      expectTemplate(
+        '{{#each goodbyes}}({{#if @first}}{{text}}! {{/if}}{{#each ../goodbyes}}{{#if @first}}{{text}}!{{/if}}{{/each}}{{#if @first}} {{text}}!{{/if}}) {{/each}}cruel {{world}}!'
+      )
+        .withInput({
+          goodbyes: [
+            { text: 'goodbye' },
+            { text: 'Goodbye' },
+            { text: 'GOODBYE' },
+          ],
+          world: 'world',
+        })
+        .withMessage('The @first variable is used')
+        .toCompileTo(
+          '(goodbye! goodbye! goodbye!) (goodbye!) (goodbye!) cruel world!'
+        );
+    });
+
+    it('each object with @first', function () {
+      expectTemplate(
+        '{{#each goodbyes}}{{#if @first}}{{text}}! {{/if}}{{/each}}cruel {{world}}!'
+      )
+        .withInput({
+          goodbyes: { foo: { text: 'goodbye' }, bar: { text: 'Goodbye' } },
+          world: 'world',
+        })
+        .withMessage('The @first variable is used')
+        .toCompileTo('goodbye! cruel world!');
+    });
+
+    it('each with @last', function () {
+      expectTemplate(
+        '{{#each goodbyes}}{{#if @last}}{{text}}! {{/if}}{{/each}}cruel {{world}}!'
+      )
+        .withInput({
+          goodbyes: [
+            { text: 'goodbye' },
+            { text: 'Goodbye' },
+            { text: 'GOODBYE' },
+          ],
+          world: 'world',
+        })
+        .withMessage('The @last variable is used')
+        .toCompileTo('GOODBYE! cruel world!');
+    });
+
+    it('each object with @last', function () {
+      expectTemplate(
+        '{{#each goodbyes}}{{#if @last}}{{text}}! {{/if}}{{/each}}cruel {{world}}!'
+      )
+        .withInput({
+          goodbyes: { foo: { text: 'goodbye' }, bar: { text: 'Goodbye' } },
+          world: 'world',
+        })
+        .withMessage('The @last variable is used')
+        .toCompileTo('Goodbye! cruel world!');
+    });
+
+    it('each with nested @last', function () {
+      expectTemplate(
+        '{{#each goodbyes}}({{#if @last}}{{text}}! {{/if}}{{#each ../goodbyes}}{{#if @last}}{{text}}!{{/if}}{{/each}}{{#if @last}} {{text}}!{{/if}}) {{/each}}cruel {{world}}!'
+      )
+        .withInput({
+          goodbyes: [
+            { text: 'goodbye' },
+            { text: 'Goodbye' },
+            { text: 'GOODBYE' },
+          ],
+          world: 'world',
+        })
+        .withMessage('The @last variable is used')
+        .toCompileTo(
+          '(GOODBYE!) (GOODBYE!) (GOODBYE! GOODBYE! GOODBYE!) cruel world!'
+        );
+    });
+
+    it('each with function argument', function () {
+      var string = '{{#each goodbyes}}{{text}}! {{/each}}cruel {{world}}!';
+
+      expectTemplate(string)
+        .withInput({
+          goodbyes: function () {
+            return [
+              { text: 'goodbye' },
+              { text: 'Goodbye' },
+              { text: 'GOODBYE' },
+            ];
+          },
+          world: 'world',
+        })
+        .withMessage(
+          'each with array function argument iterates over the contents when not empty'
+        )
+        .toCompileTo('goodbye! Goodbye! GOODBYE! cruel world!');
+
+      expectTemplate(string)
+        .withInput({
+          goodbyes: [],
+          world: 'world',
+        })
+        .withMessage(
+          'each with array function argument ignores the contents when empty'
+        )
+        .toCompileTo('cruel world!');
+    });
+
+    it('each object when last key is an empty string', function () {
+      expectTemplate(
+        '{{#each goodbyes}}{{@index}}. {{text}}! {{/each}}cruel {{world}}!'
+      )
+        .withInput({
+          goodbyes: {
+            a: { text: 'goodbye' },
+            b: { text: 'Goodbye' },
+            '': { text: 'GOODBYE' },
+          },
+          world: 'world',
+        })
+        .withMessage('Empty string key is not skipped')
+        .toCompileTo('0. goodbye! 1. Goodbye! 2. GOODBYE! cruel world!');
+    });
+
+    it('data passed to helpers', function () {
+      expectTemplate(
+        '{{#each letters}}{{this}}{{detectDataInsideEach}}{{/each}}'
+      )
+        .withInput({ letters: ['a', 'b', 'c'] })
+        .withMessage('should output data')
+        .withRuntimeOptions({
+          data: {
+            exclaim: '!',
+          },
+        })
+        .toCompileTo('a!b!c!');
+    });
+
+    it('each on implicit context', function () {
+      expectTemplate('{{#each}}{{text}}! {{/each}}cruel world!').toThrow(
+        handlebarsEnv.Exception,
+        'Must pass iterator to #each'
+      );
+    });
+
+    it('each on Map', function () {
+      var map = new Map([
+        [1, 'one'],
+        [2, 'two'],
+        [3, 'three'],
+      ]);
+
+      expectTemplate('{{#each map}}{{@key}}(i{{@index}}) {{.}} {{/each}}')
+        .withInput({ map: map })
+        .toCompileTo('1(i0) one 2(i1) two 3(i2) three ');
+
+      expectTemplate('{{#each map}}{{#if @first}}{{.}}{{/if}}{{/each}}')
+        .withInput({ map: map })
+        .toCompileTo('one');
+
+      expectTemplate('{{#each map}}{{#if @last}}{{.}}{{/if}}{{/each}}')
+        .withInput({ map: map })
+        .toCompileTo('three');
+
+      expectTemplate('{{#each map}}{{.}}{{/each}}not-in-each')
+        .withInput({ map: new Map() })
+        .toCompileTo('not-in-each');
+    });
+
+    it('each on Set', function () {
+      var set = new Set([1, 2, 3]);
+
+      expectTemplate('{{#each set}}{{@key}}(i{{@index}}) {{.}} {{/each}}')
+        .withInput({ set: set })
+        .toCompileTo('0(i0) 1 1(i1) 2 2(i2) 3 ');
+
+      expectTemplate('{{#each set}}{{#if @first}}{{.}}{{/if}}{{/each}}')
+        .withInput({ set: set })
+        .toCompileTo('1');
+
+      expectTemplate('{{#each set}}{{#if @last}}{{.}}{{/if}}{{/each}}')
+        .withInput({ set: set })
+        .toCompileTo('3');
+
+      expectTemplate('{{#each set}}{{.}}{{/each}}not-in-each')
+        .withInput({ set: new Set() })
+        .toCompileTo('not-in-each');
+    });
+
+    if (global.Symbol && global.Symbol.iterator) {
+      it('each on iterable', function () {
+        function Iterator(arr) {
+          this.arr = arr;
+          this.index = 0;
+        }
+        Iterator.prototype.next = function () {
+          var value = this.arr[this.index];
+          var done = this.index === this.arr.length;
+          if (!done) {
+            this.index++;
+          }
+          return { value: value, done: done };
+        };
+        function Iterable(arr) {
+          this.arr = arr;
+        }
+        Iterable.prototype[global.Symbol.iterator] = function () {
+          return new Iterator(this.arr);
+        };
+        var string = '{{#each goodbyes}}{{text}}! {{/each}}cruel {{world}}!';
+
+        expectTemplate(string)
+          .withInput({
+            goodbyes: new Iterable([
+              { text: 'goodbye' },
+              { text: 'Goodbye' },
+              { text: 'GOODBYE' },
+            ]),
+            world: 'world',
+          })
+          .withMessage(
+            'each with array argument iterates over the contents when not empty'
+          )
+          .toCompileTo('goodbye! Goodbye! GOODBYE! cruel world!');
+
+        expectTemplate(string)
+          .withInput({
+            goodbyes: new Iterable([]),
+            world: 'world',
+          })
+          .withMessage(
+            'each with array argument ignores the contents when empty'
+          )
+          .toCompileTo('cruel world!');
+      });
+    }
+  });
+
+  describe('#log', function () {
+    /* eslint-disable no-console */
+    if (typeof console === 'undefined') {
+      return;
+    }
+
+    var $log, $info, $error;
+    beforeEach(function () {
+      $log = console.log;
+      $info = console.info;
+      $error = console.error;
+    });
+    afterEach(function () {
+      console.log = $log;
+      console.info = $info;
+      console.error = $error;
+    });
+
+    it('should call logger at default level', function () {
+      var levelArg, logArg;
+      handlebarsEnv.log = function (level, arg) {
+        levelArg = level;
+        logArg = arg;
+      };
+
+      expectTemplate('{{log blah}}')
+        .withInput({ blah: 'whee' })
+        .withMessage('log should not display')
+        .toCompileTo('');
+      expect(levelArg).toBe(1);
+      expect(logArg).toBe('whee');
+    });
+
+    it('should call logger at data level', function () {
+      var levelArg, logArg;
+      handlebarsEnv.log = function (level, arg) {
+        levelArg = level;
+        logArg = arg;
+      };
+
+      expectTemplate('{{log blah}}')
+        .withInput({ blah: 'whee' })
+        .withRuntimeOptions({ data: { level: '03' } })
+        .withCompileOptions({ data: true })
+        .toCompileTo('');
+      expect(levelArg).toBe('03');
+      expect(logArg).toBe('whee');
+    });
+
+    it('should output to info', function () {
+      var called;
+
+      console.info = function (info) {
+        expect(info).toBe('whee');
+        called = true;
+        console.info = $info;
+        console.log = $log;
+      };
+      console.log = function (log) {
+        expect(log).toBe('whee');
+        called = true;
+        console.info = $info;
+        console.log = $log;
+      };
+
+      expectTemplate('{{log blah}}')
+        .withInput({ blah: 'whee' })
+        .toCompileTo('');
+      expect(called).toBe(true);
+    });
+
+    it('should log at data level', function () {
+      var called;
+
+      console.error = function (log) {
+        expect(log).toBe('whee');
+        called = true;
+        console.error = $error;
+      };
+
+      expectTemplate('{{log blah}}')
+        .withInput({ blah: 'whee' })
+        .withRuntimeOptions({ data: { level: '03' } })
+        .withCompileOptions({ data: true })
+        .toCompileTo('');
+      expect(called).toBe(true);
+    });
+
+    it('should handle missing logger', function () {
+      var called = false;
+
+      console.error = undefined;
+      console.log = function (log) {
+        expect(log).toBe('whee');
+        called = true;
+        console.log = $log;
+      };
+
+      expectTemplate('{{log blah}}')
+        .withInput({ blah: 'whee' })
+        .withRuntimeOptions({ data: { level: '03' } })
+        .withCompileOptions({ data: true })
+        .toCompileTo('');
+      expect(called).toBe(true);
+    });
+
+    it('should handle string log levels', function () {
+      var called;
+
+      console.error = function (log) {
+        expect(log).toBe('whee');
+        called = true;
+      };
+
+      expectTemplate('{{log blah}}')
+        .withInput({ blah: 'whee' })
+        .withRuntimeOptions({ data: { level: 'error' } })
+        .withCompileOptions({ data: true })
+        .toCompileTo('');
+      expect(called).toBe(true);
+
+      called = false;
+
+      expectTemplate('{{log blah}}')
+        .withInput({ blah: 'whee' })
+        .withRuntimeOptions({ data: { level: 'ERROR' } })
+        .withCompileOptions({ data: true })
+        .toCompileTo('');
+      expect(called).toBe(true);
+    });
+
+    it('should handle hash log levels', function () {
+      var called;
+
+      console.error = function (log) {
+        expect(log).toBe('whee');
+        called = true;
+      };
+
+      expectTemplate('{{log blah level="error"}}')
+        .withInput({ blah: 'whee' })
+        .toCompileTo('');
+      expect(called).toBe(true);
+    });
+
+    it('should handle hash log levels', function () {
+      var called = false;
+
+      console.info =
+        console.log =
+        console.error =
+        console.debug =
+          function () {
+            called = true;
+            console.info = console.log = console.error = console.debug = $log;
+          };
+
+      expectTemplate('{{log blah level="debug"}}')
+        .withInput({ blah: 'whee' })
+        .toCompileTo('');
+      expect(called).toBe(false);
+    });
+
+    it('should pass multiple log arguments', function () {
+      var called;
+
+      console.info = console.log = function (log1, log2, log3) {
+        expect(log1).toBe('whee');
+        expect(log2).toBe('foo');
+        expect(log3).toBe(1);
+        called = true;
+        console.log = $log;
+      };
+
+      expectTemplate('{{log blah "foo" 1}}')
+        .withInput({ blah: 'whee' })
+        .toCompileTo('');
+      expect(called).toBe(true);
+    });
+
+    it('should pass zero log arguments', function () {
+      var called;
+
+      console.info = console.log = function () {
+        expect(arguments.length).toBe(0);
+        called = true;
+        console.log = $log;
+      };
+
+      expectTemplate('{{log}}').withInput({ blah: 'whee' }).toCompileTo('');
+      expect(called).toBe(true);
+    });
+    /* eslint-enable no-console */
+  });
+
+  describe('#lookup', function () {
+    it('should lookup arbitrary content', function () {
+      expectTemplate('{{#each goodbyes}}{{lookup ../data .}}{{/each}}')
+        .withInput({ goodbyes: [0, 1], data: ['foo', 'bar'] })
+        .toCompileTo('foobar');
+    });
+
+    it('should not fail on undefined value', function () {
+      expectTemplate('{{#each goodbyes}}{{lookup ../bar .}}{{/each}}')
+        .withInput({ goodbyes: [0, 1], data: ['foo', 'bar'] })
+        .toCompileTo('');
+    });
+  });
+});

spec/compiler.js

@@ -0,0 +1,160 @@
+describe('compiler', function () {
+  if (!Handlebars.compile) {
+    return;
+  }
+
+  describe('#equals', function () {
+    function compile(string) {
+      var ast = Handlebars.parse(string);
+      return new Handlebars.Compiler().compile(ast, {});
+    }
+
+    it('should treat as equal', function () {
+      expect(compile('foo').equals(compile('foo'))).toBe(true);
+      expect(compile('{{foo}}').equals(compile('{{foo}}'))).toBe(true);
+      expect(compile('{{foo.bar}}').equals(compile('{{foo.bar}}'))).toBe(true);
+      expect(
+        compile('{{foo.bar baz "foo" true false bat=1}}').equals(
+          compile('{{foo.bar baz "foo" true false bat=1}}')
+        )
+      ).toBe(true);
+      expect(
+        compile('{{foo.bar (baz bat=1)}}').equals(
+          compile('{{foo.bar (baz bat=1)}}')
+        )
+      ).toBe(true);
+      expect(
+        compile('{{#foo}} {{/foo}}').equals(compile('{{#foo}} {{/foo}}'))
+      ).toBe(true);
+    });
+    it('should treat as not equal', function () {
+      expect(compile('foo').equals(compile('bar'))).toBe(false);
+      expect(compile('{{foo}}').equals(compile('{{bar}}'))).toBe(false);
+      expect(compile('{{foo.bar}}').equals(compile('{{bar.bar}}'))).toBe(false);
+      expect(
+        compile('{{foo.bar baz bat=1}}').equals(
+          compile('{{foo.bar bar bat=1}}')
+        )
+      ).toBe(false);
+      expect(
+        compile('{{foo.bar (baz bat=1)}}').equals(
+          compile('{{foo.bar (bar bat=1)}}')
+        )
+      ).toBe(false);
+      expect(
+        compile('{{#foo}} {{/foo}}').equals(compile('{{#bar}} {{/bar}}'))
+      ).toBe(false);
+      expect(
+        compile('{{#foo}} {{/foo}}').equals(compile('{{#foo}} {{foo}}{{/foo}}'))
+      ).toBe(false);
+    });
+  });
+
+  describe('#compile', function () {
+    it('should fail with invalid input', function () {
+      expect(function () {
+        Handlebars.compile(null);
+      }).toThrow(
+        'You must pass a string or Handlebars AST to Handlebars.compile. You passed null'
+      );
+      expect(function () {
+        Handlebars.compile({});
+      }).toThrow(
+        'You must pass a string or Handlebars AST to Handlebars.compile. You passed [object Object]'
+      );
+    });
+
+    it('should include the location in the error (row and column)', function () {
+      try {
+        Handlebars.compile(' \n  {{#if}}\n{{/def}}')();
+        expect.unreachable('Statement must throw exception');
+      } catch (err) {
+        expect(err.message).toBe("if doesn't match def - 2:5");
+        if (Object.getOwnPropertyDescriptor(err, 'column').writable) {
+          // In Safari 8, the column-property is read-only. This means that even if it is set with defineProperty,
+          // its value won't change (https://github.com/jquery/esprima/issues/1290#issuecomment-132455482)
+          // Since this was neither working in Handlebars 3 nor in 4.0.5, we only check the column for other browsers.
+          expect(err.column).toBe(5);
+        }
+        expect(err.lineNumber).toBe(2);
+      }
+    });
+
+    it('should include the location as enumerable property', function () {
+      try {
+        Handlebars.compile(' \n  {{#if}}\n{{/def}}')();
+        expect.unreachable('Statement must throw exception');
+      } catch (err) {
+        expect(Object.prototype.propertyIsEnumerable.call(err, 'column')).toBe(
+          true
+        );
+      }
+    });
+
+    it('can utilize AST instance', function () {
+      expect(
+        Handlebars.compile({
+          type: 'Program',
+          body: [{ type: 'ContentStatement', value: 'Hello' }],
+        })()
+      ).toBe('Hello');
+    });
+
+    it('can pass through an empty string', function () {
+      expect(Handlebars.compile('')()).toBe('');
+    });
+
+    it('throws on desupported options', function () {
+      expect(function () {
+        Handlebars.compile('Dudes', { trackIds: true });
+      }).toThrow(
+        'TrackIds and stringParams are no longer supported. See Github #1145'
+      );
+      expect(function () {
+        Handlebars.compile('Dudes', { stringParams: true });
+      }).toThrow(
+        'TrackIds and stringParams are no longer supported. See Github #1145'
+      );
+    });
+
+    it('should not modify the options.data property(GH-1327)', function () {
+      var options = { data: [{ a: 'foo' }, { a: 'bar' }] };
+      Handlebars.compile('{{#each data}}{{@index}}:{{a}} {{/each}}', options)();
+      expect(options).toStrictEqual({ data: [{ a: 'foo' }, { a: 'bar' }] });
+    });
+
+    it('should not modify the options.knownHelpers property(GH-1327)', function () {
+      var options = { knownHelpers: {} };
+      Handlebars.compile('{{#each data}}{{@index}}:{{a}} {{/each}}', options)();
+      expect(options).toStrictEqual({ knownHelpers: {} });
+    });
+  });
+
+  describe('#precompile', function () {
+    it('should fail with invalid input', function () {
+      expect(function () {
+        Handlebars.precompile(null);
+      }).toThrow(
+        'You must pass a string or Handlebars AST to Handlebars.compile. You passed null'
+      );
+      expect(function () {
+        Handlebars.precompile({});
+      }).toThrow(
+        'You must pass a string or Handlebars AST to Handlebars.compile. You passed [object Object]'
+      );
+    });
+
+    it('can utilize AST instance', function () {
+      expect(
+        Handlebars.precompile({
+          type: 'Program',
+          body: [{ type: 'ContentStatement', value: 'Hello' }],
+        })
+      ).toMatch(/return "Hello"/);
+    });
+
+    it('can pass through an empty string', function () {
+      expect(Handlebars.precompile('')).toMatch(/return ""/);
+    });
+  });
+});

spec/data.js

@@ -0,0 +1,278 @@
+describe('data', function () {
+  it('passing in data to a compiled function that expects data - works with helpers', function () {
+    expectTemplate('{{hello}}')
+      .withCompileOptions({ data: true })
+      .withHelper('hello', function (options) {
+        return options.data.adjective + ' ' + this.noun;
+      })
+      .withRuntimeOptions({ data: { adjective: 'happy' } })
+      .withInput({ noun: 'cat' })
+      .withMessage('Data output by helper')
+      .toCompileTo('happy cat');
+  });
+
+  it('data can be looked up via @foo', function () {
+    expectTemplate('{{@hello}}')
+      .withRuntimeOptions({ data: { hello: 'hello' } })
+      .withMessage('@foo retrieves template data')
+      .toCompileTo('hello');
+  });
+
+  it('deep @foo triggers automatic top-level data', function () {
+    var helpers = Handlebars.createFrame(handlebarsEnv.helpers);
+
+    helpers.let = function (options) {
+      var frame = Handlebars.createFrame(options.data);
+
+      for (var prop in options.hash) {
+        if (prop in options.hash) {
+          frame[prop] = options.hash[prop];
+        }
+      }
+      return options.fn(this, { data: frame });
+    };
+
+    expectTemplate(
+      '{{#let world="world"}}{{#if foo}}{{#if foo}}Hello {{@world}}{{/if}}{{/if}}{{/let}}'
+    )
+      .withInput({ foo: true })
+      .withHelpers(helpers)
+      .withMessage('Automatic data was triggered')
+      .toCompileTo('Hello world');
+  });
+
+  it('parameter data can be looked up via @foo', function () {
+    expectTemplate('{{hello @world}}')
+      .withRuntimeOptions({ data: { world: 'world' } })
+      .withHelper('hello', function (noun) {
+        return 'Hello ' + noun;
+      })
+      .withMessage('@foo as a parameter retrieves template data')
+      .toCompileTo('Hello world');
+  });
+
+  it('hash values can be looked up via @foo', function () {
+    expectTemplate('{{hello noun=@world}}')
+      .withRuntimeOptions({ data: { world: 'world' } })
+      .withHelper('hello', function (options) {
+        return 'Hello ' + options.hash.noun;
+      })
+      .withMessage('@foo as a parameter retrieves template data')
+      .toCompileTo('Hello world');
+  });
+
+  it('nested parameter data can be looked up via @foo.bar', function () {
+    expectTemplate('{{hello @world.bar}}')
+      .withRuntimeOptions({ data: { world: { bar: 'world' } } })
+      .withHelper('hello', function (noun) {
+        return 'Hello ' + noun;
+      })
+      .withMessage('@foo as a parameter retrieves template data')
+      .toCompileTo('Hello world');
+  });
+
+  it('nested parameter data does not fail with @world.bar', function () {
+    expectTemplate('{{hello @world.bar}}')
+      .withRuntimeOptions({ data: { foo: { bar: 'world' } } })
+      .withHelper('hello', function (noun) {
+        return 'Hello ' + noun;
+      })
+      .withMessage('@foo as a parameter retrieves template data')
+      .toCompileTo('Hello undefined');
+  });
+
+  it('parameter data throws when using complex scope references', function () {
+    expectTemplate(
+      '{{#goodbyes}}{{text}} cruel {{@foo/../name}}! {{/goodbyes}}'
+    ).toThrow(Error);
+  });
+
+  it('data can be functions', function () {
+    expectTemplate('{{@hello}}')
+      .withRuntimeOptions({
+        data: {
+          hello: function () {
+            return 'hello';
+          },
+        },
+      })
+      .toCompileTo('hello');
+  });
+
+  it('data can be functions with params', function () {
+    expectTemplate('{{@hello "hello"}}')
+      .withRuntimeOptions({
+        data: {
+          hello: function (arg) {
+            return arg;
+          },
+        },
+      })
+      .toCompileTo('hello');
+  });
+
+  it('data is inherited downstream', function () {
+    expectTemplate(
+      '{{#let foo=1 bar=2}}{{#let foo=bar.baz}}{{@bar}}{{@foo}}{{/let}}{{@foo}}{{/let}}'
+    )
+      .withInput({ bar: { baz: 'hello world' } })
+      .withCompileOptions({ data: true })
+      .withHelper('let', function (options) {
+        var frame = Handlebars.createFrame(options.data);
+        for (var prop in options.hash) {
+          if (prop in options.hash) {
+            frame[prop] = options.hash[prop];
+          }
+        }
+        return options.fn(this, { data: frame });
+      })
+      .withRuntimeOptions({ data: {} })
+      .withMessage('data variables are inherited downstream')
+      .toCompileTo('2hello world1');
+  });
+
+  it('passing in data to a compiled function that expects data - works with helpers in partials', function () {
+    expectTemplate('{{>myPartial}}')
+      .withCompileOptions({ data: true })
+      .withPartial('myPartial', '{{hello}}')
+      .withHelper('hello', function (options) {
+        return options.data.adjective + ' ' + this.noun;
+      })
+      .withInput({ noun: 'cat' })
+      .withRuntimeOptions({ data: { adjective: 'happy' } })
+      .withMessage('Data output by helper inside partial')
+      .toCompileTo('happy cat');
+  });
+
+  it('passing in data to a compiled function that expects data - works with helpers and parameters', function () {
+    expectTemplate('{{hello world}}')
+      .withCompileOptions({ data: true })
+      .withHelper('hello', function (noun, options) {
+        return options.data.adjective + ' ' + noun + (this.exclaim ? '!' : '');
+      })
+      .withInput({ exclaim: true, world: 'world' })
+      .withRuntimeOptions({ data: { adjective: 'happy' } })
+      .withMessage('Data output by helper')
+      .toCompileTo('happy world!');
+  });
+
+  it('passing in data to a compiled function that expects data - works with block helpers', function () {
+    expectTemplate('{{#hello}}{{world}}{{/hello}}')
+      .withCompileOptions({
+        data: true,
+      })
+      .withHelper('hello', function (options) {
+        return options.fn(this);
+      })
+      .withHelper('world', function (options) {
+        return options.data.adjective + ' world' + (this.exclaim ? '!' : '');
+      })
+      .withInput({ exclaim: true })
+      .withRuntimeOptions({ data: { adjective: 'happy' } })
+      .withMessage('Data output by helper')
+      .toCompileTo('happy world!');
+  });
+
+  it('passing in data to a compiled function that expects data - works with block helpers that use ..', function () {
+    expectTemplate('{{#hello}}{{world ../zomg}}{{/hello}}')
+      .withCompileOptions({ data: true })
+      .withHelper('hello', function (options) {
+        return options.fn({ exclaim: '?' });
+      })
+      .withHelper('world', function (thing, options) {
+        return options.data.adjective + ' ' + thing + (this.exclaim || '');
+      })
+      .withInput({ exclaim: true, zomg: 'world' })
+      .withRuntimeOptions({ data: { adjective: 'happy' } })
+      .withMessage('Data output by helper')
+      .toCompileTo('happy world?');
+  });
+
+  it('passing in data to a compiled function that expects data - data is passed to with block helpers where children use ..', function () {
+    expectTemplate('{{#hello}}{{world ../zomg}}{{/hello}}')
+      .withCompileOptions({ data: true })
+      .withHelper('hello', function (options) {
+        return options.data.accessData + ' ' + options.fn({ exclaim: '?' });
+      })
+      .withHelper('world', function (thing, options) {
+        return options.data.adjective + ' ' + thing + (this.exclaim || '');
+      })
+      .withInput({ exclaim: true, zomg: 'world' })
+      .withRuntimeOptions({ data: { adjective: 'happy', accessData: '#win' } })
+      .withMessage('Data output by helper')
+      .toCompileTo('#win happy world?');
+  });
+
+  it('you can override inherited data when invoking a helper', function () {
+    expectTemplate('{{#hello}}{{world zomg}}{{/hello}}')
+      .withCompileOptions({ data: true })
+      .withHelper('hello', function (options) {
+        return options.fn(
+          { exclaim: '?', zomg: 'world' },
+          { data: { adjective: 'sad' } }
+        );
+      })
+      .withHelper('world', function (thing, options) {
+        return options.data.adjective + ' ' + thing + (this.exclaim || '');
+      })
+      .withInput({ exclaim: true, zomg: 'planet' })
+      .withRuntimeOptions({ data: { adjective: 'happy' } })
+      .withMessage('Overridden data output by helper')
+      .toCompileTo('sad world?');
+  });
+
+  it('you can override inherited data when invoking a helper with depth', function () {
+    expectTemplate('{{#hello}}{{world ../zomg}}{{/hello}}')
+      .withCompileOptions({ data: true })
+      .withHelper('hello', function (options) {
+        return options.fn({ exclaim: '?' }, { data: { adjective: 'sad' } });
+      })
+      .withHelper('world', function (thing, options) {
+        return options.data.adjective + ' ' + thing + (this.exclaim || '');
+      })
+      .withInput({ exclaim: true, zomg: 'world' })
+      .withRuntimeOptions({ data: { adjective: 'happy' } })
+      .withMessage('Overridden data output by helper')
+      .toCompileTo('sad world?');
+  });
+
+  describe('@root', function () {
+    it('the root context can be looked up via @root', function () {
+      expectTemplate('{{@root.foo}}')
+        .withInput({ foo: 'hello' })
+        .withRuntimeOptions({ data: {} })
+        .toCompileTo('hello');
+
+      expectTemplate('{{@root.foo}}')
+        .withInput({ foo: 'hello' })
+        .toCompileTo('hello');
+    });
+
+    it('passed root values take priority', function () {
+      expectTemplate('{{@root.foo}}')
+        .withInput({ foo: 'should not be used' })
+        .withRuntimeOptions({ data: { root: { foo: 'hello' } } })
+        .toCompileTo('hello');
+    });
+  });
+
+  describe('nesting', function () {
+    it('the root context can be looked up via @root', function () {
+      expectTemplate(
+        '{{#helper}}{{#helper}}{{@./depth}} {{@../depth}} {{@../../depth}}{{/helper}}{{/helper}}'
+      )
+        .withInput({ foo: 'hello' })
+        .withHelper('helper', function (options) {
+          var frame = Handlebars.createFrame(options.data);
+          frame.depth = options.data.depth + 1;
+          return options.fn(this, { data: frame });
+        })
+        .withRuntimeOptions({
+          data: {
+            depth: 0,
+          },
+        })
+        .toCompileTo('2 1 0');
+    });
+  });
+});

spec/env/browser-vitest-pre.js

@@ -0,0 +1,6 @@
+// Pre-setup for browser tests. Must run before the main setup file
+// imports the Handlebars library, so that noConflict() captures this value.
+globalThis.Handlebars = 'no-conflict';
+
+// Polyfill Node.js 'global' for specs that reference it at module level
+globalThis.global = globalThis;

spec/env/browser-vitest.js

@@ -0,0 +1,27 @@
+import './common.js';
+import Handlebars from '../../lib/handlebars.js';
+
+globalThis.Handlebars = Handlebars;
+
+globalThis.CompilerContext = {
+  browser: true,
+
+  compile: function (template, options) {
+    var templateSpec = handlebarsEnv.precompile(template, options);
+    return handlebarsEnv.template(safeEval(templateSpec));
+  },
+  compileWithPartial: function (template, options) {
+    return handlebarsEnv.compile(template, options);
+  },
+};
+
+function safeEval(templateSpec) {
+  /* eslint-disable no-eval, no-console */
+  try {
+    return eval('(' + templateSpec + ')');
+  } catch (err) {
+    console.error(templateSpec);
+    throw err;
+  }
+  /* eslint-enable no-eval, no-console */
+}

spec/env/browser.js

@@ -0,0 +1,36 @@
+require('./common');
+
+var fs = require('fs'),
+  vm = require('vm');
+
+global.Handlebars = 'no-conflict';
+
+var filename = 'dist/handlebars.js';
+var distHandlebars = fs.readFileSync(
+  require.resolve('../../' + filename),
+  'utf-8'
+);
+vm.runInThisContext(distHandlebars, filename);
+
+global.CompilerContext = {
+  browser: true,
+
+  compile: function (template, options) {
+    var templateSpec = handlebarsEnv.precompile(template, options);
+    return handlebarsEnv.template(safeEval(templateSpec));
+  },
+  compileWithPartial: function (template, options) {
+    return handlebarsEnv.compile(template, options);
+  },
+};
+
+function safeEval(templateSpec) {
+  /* eslint-disable no-eval, no-console */
+  try {
+    return eval('(' + templateSpec + ')');
+  } catch (err) {
+    console.error(templateSpec);
+    throw err;
+  }
+  /* eslint-enable no-eval, no-console */
+}

spec/env/common.js

@@ -0,0 +1,133 @@
+var global = globalThis;
+
+global.expectTemplate = function (templateAsString) {
+  return new HandlebarsTestBench(templateAsString);
+};
+
+function HandlebarsTestBench(templateAsString) {
+  this.templateAsString = templateAsString;
+  this.helpers = {};
+  this.partials = {};
+  this.decorators = {};
+  this.input = {};
+  this.message =
+    'Template' + templateAsString + ' does not evaluate to expected output';
+  this.compileOptions = {};
+  this.runtimeOptions = {};
+}
+
+HandlebarsTestBench.prototype.withInput = function (input) {
+  this.input = input;
+  return this;
+};
+
+HandlebarsTestBench.prototype.withHelper = function (name, helperFunction) {
+  this.helpers[name] = helperFunction;
+  return this;
+};
+
+HandlebarsTestBench.prototype.withHelpers = function (helperFunctions) {
+  var self = this;
+  Object.keys(helperFunctions).forEach(function (name) {
+    self.withHelper(name, helperFunctions[name]);
+  });
+  return this;
+};
+
+HandlebarsTestBench.prototype.withPartial = function (name, partialAsString) {
+  this.partials[name] = partialAsString;
+  return this;
+};
+
+HandlebarsTestBench.prototype.withPartials = function (partials) {
+  var self = this;
+  Object.keys(partials).forEach(function (name) {
+    self.withPartial(name, partials[name]);
+  });
+  return this;
+};
+
+HandlebarsTestBench.prototype.withDecorator = function (
+  name,
+  decoratorFunction
+) {
+  this.decorators[name] = decoratorFunction;
+  return this;
+};
+
+HandlebarsTestBench.prototype.withDecorators = function (decorators) {
+  var self = this;
+  Object.keys(decorators).forEach(function (name) {
+    self.withDecorator(name, decorators[name]);
+  });
+  return this;
+};
+
+HandlebarsTestBench.prototype.withCompileOptions = function (compileOptions) {
+  this.compileOptions = compileOptions;
+  return this;
+};
+
+HandlebarsTestBench.prototype.withRuntimeOptions = function (runtimeOptions) {
+  this.runtimeOptions = runtimeOptions;
+  return this;
+};
+
+HandlebarsTestBench.prototype.withMessage = function (message) {
+  this.message = message;
+  return this;
+};
+
+HandlebarsTestBench.prototype.toCompileTo = function (expectedOutputAsString) {
+  expect(this._compileAndExecute()).toBe(expectedOutputAsString);
+};
+
+HandlebarsTestBench.prototype.toThrow = function (errorLike, errMsgMatcher) {
+  var self = this;
+  var caught;
+  try {
+    self._compileAndExecute();
+  } catch (e) {
+    caught = e;
+  }
+
+  expect(caught).toBeDefined();
+
+  if (typeof errorLike === 'function') {
+    expect(caught).toBeInstanceOf(errorLike);
+    if (errMsgMatcher) {
+      expect(caught.message).toMatch(errMsgMatcher);
+    }
+  } else if (errorLike) {
+    // errorLike is a string or regex message matcher (single-argument form)
+    expect(caught.message).toMatch(errorLike);
+  }
+};
+
+HandlebarsTestBench.prototype._compileAndExecute = function () {
+  var compile =
+    Object.keys(this.partials).length > 0
+      ? CompilerContext.compileWithPartial
+      : CompilerContext.compile;
+
+  var combinedRuntimeOptions = this._combineRuntimeOptions();
+
+  var template = compile(this.templateAsString, this.compileOptions);
+  return template(this.input, combinedRuntimeOptions);
+};
+
+HandlebarsTestBench.prototype._combineRuntimeOptions = function () {
+  var self = this;
+  var combinedRuntimeOptions = {};
+  Object.keys(this.runtimeOptions).forEach(function (key) {
+    combinedRuntimeOptions[key] = self.runtimeOptions[key];
+  });
+  combinedRuntimeOptions.helpers = this.helpers;
+  combinedRuntimeOptions.partials = this.partials;
+  combinedRuntimeOptions.decorators = this.decorators;
+  return combinedRuntimeOptions;
+};
+
+beforeEach(function () {
+  global.handlebarsEnv = Handlebars.create();
+});

spec/env/node.js

@@ -0,0 +1,24 @@
+require('./common');
+
+global.Handlebars = require('../../lib');
+
+global.CompilerContext = {
+  compile: function (template, options) {
+    var templateSpec = handlebarsEnv.precompile(template, options);
+    return handlebarsEnv.template(safeEval(templateSpec));
+  },
+  compileWithPartial: function (template, options) {
+    return handlebarsEnv.compile(template, options);
+  },
+};
+
+function safeEval(templateSpec) {
+  /* eslint-disable no-eval, no-console */
+  try {
+    return eval('(' + templateSpec + ')');
+  } catch (err) {
+    console.error(templateSpec);
+    throw err;
+  }
+  /* eslint-enable no-eval, no-console */
+}

spec/expected/bom.amd.js

@@ -0,0 +1,6 @@
+define(['handlebars.runtime'], function(Handlebars) {
+    Handlebars = Handlebars["default"];  var template = Handlebars.template, templates = Handlebars.templates = Handlebars.templates || {};
+  return templates['bom'] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+      return "a";
+  },"useData":true});
+  });

spec/expected/compiled.string.txt

@@ -0,0 +1,3 @@
+{"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+    return "<div>Test String</div>";
+},"useData":true}

spec/expected/empty.amd.js

@@ -0,0 +1,6 @@
+define(['handlebars.runtime'], function(Handlebars) {
+  Handlebars = Handlebars["default"];  var template = Handlebars.template, templates = Handlebars.templates = Handlebars.templates || {};
+return templates['empty'] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+    return "";
+},"useData":true});
+});

spec/expected/empty.amd.min.js

@@ -0,0 +1 @@
+define(["handlebars.runtime"],function(e){var t=(e=e.default).template;return(e.templates=e.templates||{}).empty=t({compiler:[8,">= 4.3.0"],main:function(e,t,a,n,r){return""},useData:!0})});