Converted XModule to JavaScript. Added Jasmine tests.

Part of the process for removing CoffeeScript from
edx-platform dependencies. Covering XModule with JavaScript
Jasmine unit tests.

common/lib/xmodule/xmodule/js/spec/.gitignore

@@ -6,3 +6,4 @@
 # Tests for Time are written in pure JavaScript.
 !time_spec.js
 !collapsible_spec.js
+!xmodule_spec.js

common/lib/xmodule/xmodule/js/spec/xmodule_spec.js

+(function () {
+    'use strict';
+
+    describe('XBlockToXModuleShim', function () {
+        describe('definition', function () {
+            it('XBlockToXModuleShim is defined, and is a function', function () {
+                expect($.isFunction(XBlockToXModuleShim)).toBe(true);
+            });
+        });
+
+        describe('implementation', function () {
+            var el,
+                videoModule = {
+                    'module': 'video_module'
+                },
+                editCallback,
+                displayCallback,
+                removeNone,
+                removeVideo;
+
+            beforeEach(function () {
+                el = $('<div />');
+
+                if (window.None) {
+                    spyOn(window, 'None');
+                    removeNone = false;
+                } else {
+                    window.None = jasmine.createSpy('None');
+                    removeNone = true;
+                }
+
+                if (window.Video) {
+                    spyOn(window, 'Video');
+                    removeVideo = false;
+                } else {
+                    window.Video = jasmine.createSpy('Video');
+                    removeVideo = true;
+                }
+                window.Video.andReturn(videoModule);
+
+                editCallback = jasmine.createSpy('editCallback');
+                $(document).on('XModule.loaded.edit', editCallback);
+                spyOnEvent($(document), 'XModule.loaded.edit');
+
+                displayCallback = jasmine.createSpy('displayCallback');
+                $(document).on('XModule.loaded.display', displayCallback);
+                spyOnEvent($(document), 'XModule.loaded.display');
+            });
+
+            afterEach(function () {
+                el = null;
+
+                if (removeNone) {
+                    window.None = undefined;
+                }
+                if (removeVideo) {
+                    window.Video = undefined;
+                }
+            });
+
+            it('if element module is of type None, nothing happens', function () {
+                el.data('type', 'None');
+
+                expect(XBlockToXModuleShim(null, el)).toBeUndefined();
+                expect(window.None).not.toHaveBeenCalled();
+            });
+
+            it('if element module is of type Video, Video module constructor is called', function () {
+                el.data('type', 'Video');
+
+                expect(XBlockToXModuleShim(null, el)).toEqual(videoModule);
+                expect(window.Video).toHaveBeenCalled();
+
+                expect('XModule.loaded.edit').not.toHaveBeenTriggeredOn(document);
+                expect('XModule.loaded.display').not.toHaveBeenTriggeredOn(document);
+            });
+
+            it('if element has class "xmodule_edit"', function () {
+                el.data('type', 'Video')
+                    .addClass('xmodule_edit');
+                XBlockToXModuleShim(null, el);
+                expect('XModule.loaded.edit').toHaveBeenTriggeredOn($(document));
+                expect(editCallback).toHaveBeenCalledWith(jasmine.any($.Event), el, videoModule);
+                expect('XModule.loaded.display').not.toHaveBeenTriggeredOn($(document));
+            });
+
+            it('if element has class "xmodule_display"', function () {
+                el.data('type', 'Video')
+                    .addClass('xmodule_display');
+                XBlockToXModuleShim(null, el);
+                expect('XModule.loaded.edit').not.toHaveBeenTriggeredOn($(document));
+                expect('XModule.loaded.display').toHaveBeenTriggeredOn($(document));
+                expect(displayCallback).toHaveBeenCalledWith(jasmine.any($.Event), el, videoModule);
+            });
+
+            it('if element has classes "xmodule_edit", and "xmodule_display"', function () {
+                el.data('type', 'Video')
+                    .addClass('xmodule_edit')
+                    .addClass('xmodule_display');
+                XBlockToXModuleShim(null, el);
+                expect('XModule.loaded.edit').toHaveBeenTriggeredOn($(document));
+                expect('XModule.loaded.display').toHaveBeenTriggeredOn($(document));
+            });
+
+            it('element is of an unknown Module type, console.error() is called if it is defined', function () {
+                var oldConsole = window.console;
+
+                if (window.console && window.console.error) {
+                    spyOn(window.console, 'error');
+                } else {
+                    window.console = jasmine.createSpy('console.error');
+                }
+
+                el.data('type', 'UnknownModule');
+                expect(XBlockToXModuleShim(null, el)).toBeUndefined();
+
+                expect(console.error).toHaveBeenCalledWith(
+                    'Unable to load UnknownModule: window[moduleType] is not a constructor'
+                );
+
+                window.console = oldConsole;
+            });
+
+            it('element is of an unknown Module type, JavaScript throws if console.error() is not defined', function () {
+                var oldConsole = window.console,
+                    testFunction = function () {
+                        return XBlockToXModuleShim(null, el);
+                    };
+
+
+                if (window.console) {
+                    window.console = undefined;
+                }
+
+                el.data('type', 'UnknownModule');
+                expect(testFunction).toThrow();
+
+                window.console = oldConsole;
+            });
+        });
+    });
+
+    describe('XModule.Descriptor', function () {
+        describe('definition', function () {
+            it('XModule is defined, and is a plain object', function () {
+                expect($.isPlainObject(XModule)).toBe(true);
+            });
+
+            it('XModule.Descriptor is defined, and is a function', function () {
+                expect($.isFunction(XModule.Descriptor)).toBe(true);
+            });
+
+            it('XModule.Descriptor has a complete prototype', function () {
+                expect($.isFunction(XModule.Descriptor.prototype.onUpdate)).toBe(true);
+                expect($.isFunction(XModule.Descriptor.prototype.update)).toBe(true);
+                expect($.isFunction(XModule.Descriptor.prototype.save)).toBe(true);
+            });
+        });
+
+        describe('implementation', function () {
+            var el, obj, callback, length;
+
+            // This is a dummy callback.
+            callback = function () {
+                var x = 1;
+
+                return x + 1;
+            };
+
+            beforeEach(function () {
+                el = 'dummy object';
+                obj = new XModule.Descriptor(el);
+
+                spyOn(obj, 'save').andCallThrough();
+            });
+
+            afterEach(function () {
+                el = null;
+                obj = null;
+
+                length = undefined;
+            });
+
+            it('Descriptor is a proper constructor function', function () {
+                expect(obj.hasOwnProperty('element')).toBe(true);
+                expect(obj.element).toBe(el);
+
+                expect(obj.hasOwnProperty('update')).toBe(true);
+            });
+
+            it('Descriptor.onUpdate called for the first time', function () {
+                expect(obj.hasOwnProperty('callbacks')).toBe(false);
+                obj.onUpdate(callback);
+                expect(obj.hasOwnProperty('callbacks')).toBe(true);
+                expect($.isArray(obj.callbacks)).toBe(true);
+
+                length = obj.callbacks.length;
+                expect(length).toBe(1);
+                expect(obj.callbacks[length - 1]).toBe(callback);
+            });
+
+            it('Descriptor.onUpdate called for Nth time', function () {
+                // In this test it doesn't matter what obj.callbacks
+                // consists of.
+                obj.callbacks = ['test1', 'test2', 'test3'];
+
+                obj.onUpdate(callback);
+
+                length = obj.callbacks.length;
+                expect(length).toBe(4);
+                expect(obj.callbacks[length - 1]).toBe(callback);
+            });
+
+            it('Descriptor.save returns a blank object', function () {
+                // NOTE: In the future the implementation of .save()
+                // method may change!
+                expect(obj.save()).toEqual({});
+            });
+
+            it('Descriptor.update triggers all callbacks with whatever .save() returns', function () {
+                var callback1 = jasmine.createSpy('callback1'),
+                    callback2 = jasmine.createSpy('callback2'),
+                    testValue = 'test 123';
+
+                obj.onUpdate(callback1);
+                obj.onUpdate(callback2);
+
+                obj.save.andReturn(testValue);
+                obj.update();
+
+                expect(callback1).toHaveBeenCalledWith(testValue);
+                expect(callback2).toHaveBeenCalledWith(testValue);
+            });
+        });
+    });
+}).call(this);

common/lib/xmodule/xmodule/js/src/.gitignore

@@ -12,3 +12,4 @@
 # Converted to JS from CoffeeScript.
 !time.js
 !collapsible.js
+!xmodule.js

common/lib/xmodule/xmodule/js/src/xmodule.coffee

-@XModule = {}
-
-@XBlockToXModuleShim = (runtime, element) ->
-  ###
-  Load a single module (either an edit module or a display module)
-  from the supplied element, which should have a data-type attribute
-  specifying the class to load
-  ###
-  moduleType = $(element).data('type')
-  if moduleType == 'None'
-    return
-
-  try
-    module = new window[moduleType](element)
-    if $(element).hasClass('xmodule_edit')
-      $(document).trigger('XModule.loaded.edit', [element, module])
-
-    if $(element).hasClass('xmodule_display')
-      $(document).trigger('XModule.loaded.display', [element, module])
-
-    return module
-
-  catch error
-    if window.console and console.log
-      console.error "Unable to load #{moduleType}: #{error.message}"
-    else
-      throw error
-
-
-class @XModule.Descriptor
-
-  ###
-  Register a callback method to be called when the state of this
-  descriptor is updated. The callback will be passed the results
-  of calling the save method on this descriptor.
-  ###
-  onUpdate: (callback) ->
-    if ! @callbacks?
-      @callbacks = []
-
-    @callbacks.push(callback)
-
-  ###
-  Notify registered callbacks that the state of this descriptor has changed
-  ###
-  update: =>
-    data = @save()
-    callback(data) for callback in @callbacks
-
-  ###
-  Bind the module to an element. This may be called multiple times,
-  if the element content has changed and so the module needs to be rebound
-
-  @method: constructor
-  @param {html element} the .xmodule_edit section containing all of the descriptor content
-  ###
-  constructor: (@element) -> return
-
-  ###
-  Return the current state of the descriptor (to be written to the module store)
-
-  @method: save
-  @returns {object} An object containing children and data attributes (both optional).
-                    The contents of the attributes will be saved to the server
-  ###
-  save: -> return {}

common/lib/xmodule/xmodule/js/src/xmodule.js

+(function () {
+    'use strict';
+
+    var XModule = {};
+
+    XModule.Descriptor = (function () {
+        /*
+         * Bind the module to an element. This may be called multiple times,
+         * if the element content has changed and so the module needs to be rebound
+         *
+         * @method: constructor
+         * @param {html element} the .xmodule_edit section containing all of the descriptor content
+         */
+        var Descriptor = function (element) {
+            this.element = element;
+            this.update = _.bind(this.update, this);
+        };
+
+        /*
+         * Register a callback method to be called when the state of this
+         * descriptor is updated. The callback will be passed the results
+         * of calling the save method on this descriptor.
+         */
+        Descriptor.prototype.onUpdate = function (callback) {
+            if (!this.callbacks) {
+                this.callbacks = [];
+            }
+
+            this.callbacks.push(callback);
+        };
+
+        /*
+         * Notify registered callbacks that the state of this descriptor has changed
+         */
+        Descriptor.prototype.update = function () {
+            var data, callbacks, i, length;
+
+            data = this.save();
+            callbacks = this.callbacks;
+            length = callbacks.length;
+
+            $.each(callbacks, function (index, callback) {
+                callback(data);
+            });
+        };
+
+        /*
+         * Return the current state of the descriptor (to be written to the module store)
+         *
+         * @method: save
+         * @returns {object} An object containing children and data attributes (both optional).
+         *                   The contents of the attributes will be saved to the server
+         */
+        Descriptor.prototype.save = function () {
+            return {};
+        };
+
+        return Descriptor;
+    }());
+
+    this.XBlockToXModuleShim = function (runtime, element) {
+        /*
+         * Load a single module (either an edit module or a display module)
+         * from the supplied element, which should have a data-type attribute
+         * specifying the class to load
+         */
+        var moduleType = $(element).data('type'),
+            module;
+
+        if (moduleType === 'None') {
+            return;
+        }
+
+        try {
+            module = new window[moduleType](element);
+
+            if ($(element).hasClass('xmodule_edit')) {
+                $(document).trigger('XModule.loaded.edit', [element, module]);
+            }
+
+            if ($(element).hasClass('xmodule_display')) {
+                $(document).trigger('XModule.loaded.display', [element, module]);
+            }
+
+            return module;
+        } catch (error) {
+            console.error('Unable to load ' + moduleType + ': ' + error.message);
+        }
+    };
+
+    // Export this module. We do it at the end when everything is ready
+    // because some RequireJS scripts require this module. If
+    // `window.XModule` appears as defined before this file has a chance
+    // to execute fully, then there is a chance that RequireJS will execute
+    // some script prematurely.
+    this.XModule = XModule;
+}).call(this);

common/lib/xmodule/xmodule/x_module.py

@@ -64,10 +64,12 @@ class HTMLSnippet(object):
         # this means we need to make sure that all xmodules include this dependency which had been previously implicitly
         # fulfilled in a different area of code
         coffee = cls.js.setdefault('coffee', [])
-        fragment = resource_string(__name__, 'js/src/xmodule.coffee')
+        js = cls.js.setdefault('js', [])
 
-        if fragment not in coffee:
-            coffee.insert(0, fragment)
+        fragment = resource_string(__name__, 'js/src/xmodule.js')
+
+        if fragment not in js:
+            js.insert(0, fragment)
 
         return cls.js