Eslint upgrade to 19.0.0 and configuration fixes (#1294)

Original PR by @travnels, commit-message edited by @nknapp

* Upgraded eslint to 19.0.0
* Cleaned up duplicate rules 'no-extra-parens', 'quote-props'
* eslint rule 'no-empty-label' was replaced.
  Rule 'no-empty-label' was removed and replaced by: ‘no-labels’. ‘no-labels’ already in the project
* eslint rule 'space-after-keywords' has been replaced
  Rules 'space-after-keywords' and 'space-return-throw-case' wer removed and replaced by ‘keyword-spacing’.
* Added parsoer-option: sourceType='module'
* Add unnecessary=false to 'quote-props' to remove warnings about unnecessarily quoted property. 

Code corrections
* helpers.js: unused variable 'depthString' removed, detected by new eslint

.eslintrc

@@ -43,7 +43,6 @@
     "no-empty-character-class": 2,
     "no-ex-assign": 2,
     "no-extra-boolean-cast": 2,
-    "no-extra-parens": 0,
     "no-extra-semi": 2,
     "no-func-assign": 0,
 
@@ -55,7 +54,7 @@
     "no-negated-in-lhs": 2,
     "no-obj-calls": 2,
     "no-regex-spaces": 2,
-    "quote-props": [2, "as-needed", {"keywords": true}],
+    "quote-props": [2, "as-needed", {"keywords": true, "unnecessary": false}],
     "no-sparse-arrays": 0,
 
     // Optimizer and coverage will handle/highlight this and can be useful for debugging
@@ -80,7 +79,6 @@
     "no-caller": 2,
     "no-div-regex": 1,
     "no-else-return": 0,
-    "no-empty-label": 2,
     "no-eq-null": 0,
     "no-eval": 2,
     "no-extend-native": 2,
@@ -179,22 +177,23 @@
     "one-var": 0,
     "operator-assignment": 0,
     "padded-blocks": 0,
-    "quote-props": 0,
     "quotes": [2, "single", "avoid-escape"],
     "semi": 2,
     "semi-spacing": [2, {"before": false, "after": true}],
     "sort-vars": 0,
-    "space-after-keywords": [2, "always"],
+    "keyword-spacing": 2,
     "space-before-blocks": [2, "always"],
     "space-before-function-paren": [2, {"anonymous": "never", "named": "never"}],
     "space-in-brackets": 0,
     "space-in-parens": [2, "never"],
     "space-infix-ops": 2,
-    "space-return-throw-case": 2,
     "space-unary-ops": 2,
     "spaced-comment": [2, "always", {"markers": [","]}],
     "wrap-regex": 1,
 
     "no-var": 1
+  },
+  "parserOptions": {
+    "sourceType": "module"
   }
 }

lib/handlebars/compiler/helpers.js

@@ -47,8 +47,7 @@ export function preparePath(data, parts, loc) {
 
   let original = data ? '@' : '',
       dig = [],
-      depth = 0,
-      depthString = '';
+      depth = 0;
 
   for (let i = 0, l = parts.length; i < l; i++) {
     let part = parts[i].part,
@@ -62,7 +61,6 @@ export function preparePath(data, parts, loc) {
         throw new Exception('Invalid path: ' + original, {loc});
       } else if (part === '..') {
         depth++;
-        depthString += '../';
       }
     } else {
       dig.push(part);

package.json

@@ -44,7 +44,7 @@
     "grunt-contrib-copy": "0.x",
     "grunt-contrib-uglify": "0.x",
     "grunt-contrib-watch": "0.x",
-    "grunt-eslint": "^17.1.0",
+    "grunt-eslint": "19.0.x",
     "grunt-saucelabs": "8.x",
     "grunt-webpack": "^1.0.8",
     "istanbul": "kpdecker/istanbul",