Implement decorator environment and registration

lib/handlebars/base.js

@@ -1,6 +1,7 @@
 import {createFrame, extend, toString} from './utils';
 import Exception from './exception';
 import {registerDefaultHelpers} from './helpers';
+import {registerDefaultDecorators} from './decorators';
 import logger from './logger';
 
 export const VERSION = '3.0.1';
@@ -17,11 +18,13 @@ export const REVISION_CHANGES = {
 
 const objectType = '[object Object]';
 
-export function HandlebarsEnvironment(helpers, partials) {
+export function HandlebarsEnvironment(helpers, partials, decorators) {
   this.helpers = helpers || {};
   this.partials = partials || {};
+  this.decorators = decorators || {};
 
   registerDefaultHelpers(this);
+  registerDefaultDecorators(this);
 }
 
 HandlebarsEnvironment.prototype = {
@@ -54,6 +57,18 @@ HandlebarsEnvironment.prototype = {
   },
   unregisterPartial: function(name) {
     delete this.partials[name];
+  },
+
+  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];
   }
 };
 

lib/handlebars/decorators.js

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

lib/handlebars/runtime.js

@@ -153,9 +153,13 @@ export function template(templateSpec, env) {
       if (templateSpec.usePartial) {
         container.partials = container.merge(options.partials, env.partials);
       }
+      if (templateSpec.useDecorators) {
+        container.decorators = container.merge(options.decorators, env.decorators);
+      }
     } else {
       container.helpers = options.helpers;
       container.partials = options.partials;
+      container.decorators = options.decorators;
     }
   };
 

spec/blocks.js

@@ -166,4 +166,44 @@ describe('blocks', function() {
       shouldCompileTo(string, [hash, undefined, undefined, true], 'Goodbye cruel ');
     });
   });
+
+  describe('decorators', function() {
+    describe('registration', function() {
+      it('unregisters', function() {
+        handlebarsEnv.decorators = {};
+
+        handlebarsEnv.registerDecorator('foo', function() {
+          return 'fail';
+        });
+
+        equals(!!handlebarsEnv.decorators.foo, true);
+        handlebarsEnv.unregisterDecorator('foo');
+        equals(handlebarsEnv.decorators.foo, undefined);
+      });
+
+      it('allows multiple globals', function() {
+        handlebarsEnv.decorators = {};
+
+        handlebarsEnv.registerDecorator({
+          foo: function() {},
+          bar: function() {}
+        });
+
+        equals(!!handlebarsEnv.decorators.foo, true);
+        equals(!!handlebarsEnv.decorators.bar, true);
+        handlebarsEnv.unregisterDecorator('foo');
+        handlebarsEnv.unregisterDecorator('bar');
+        equals(handlebarsEnv.decorators.foo, undefined);
+        equals(handlebarsEnv.decorators.bar, undefined);
+      });
+      it('fails with multiple and args', function() {
+        shouldThrow(function() {
+          handlebarsEnv.registerDecorator({
+            world: function() { return 'world!'; },
+            testHelper: function() { return 'found it!'; }
+          }, {});
+        }, Error, 'Arg not supported with multiple decorators');
+      });
+    });
+  });
 });