Update Backbone and Underscore

Backbone now has a 1.0 release.

http://backbonejs.org/

We are approaching code freeze. I'm de-postponing this issue and marking it active. We need to get Backbone upgraded and the production version in place before code freeze.

I won't be able to get to this in the coming week.

I've been backporting Toolbar to Navbar, which is running on Backbone 1.0. So far I've only found one upgrade issue: #2139571: underscore.js fails to compare DOM nodes correctly; Toolbar JS will fail when upgraded to Backbone 1.0.0.

wimleers is currently backporting D8 Edit to D7. Those two modules are the ones using Backbone most extensively. Once he's had a chance to do that backport, we'll know what issues we'll have with an upgrade.

diff --git a/core/modules/ckeditor/js/ckeditor.admin.js b/core/modules/ckeditor/js/ckeditor.admin.js
index ccf2f71..49ca229 100644
--- a/core/modules/ckeditor/js/ckeditor.admin.js
+++ b/core/modules/ckeditor/js/ckeditor.admin.js
@@ -120,8 +120,8 @@ Drupal.ckeditor = {
       this.getCKEditorFeatures(this.model.get('hiddenEditorConfig'), this.disableFeaturesDisallowedByFilters.bind(this));
 
       // Push the active editor configuration to the textarea.
-      this.model.on('change:activeEditorConfig', this.model.sync, this.model);
-      this.model.on('change:isDirty', this.parseEditorDOM, this);
+      this.model.listenTo(this.model, 'change:activeEditorConfig', this.model.sync, this.model);
+      this.listenTo(this.model, 'change:isDirty', this.parseEditorDOM, this);
     },

I think that, in the code above

+      this.model.listenTo(this.model, 'change:activeEditorConfig', this.model.sync, this.model);

should be

+      this.listenTo(this.model, 'change:activeEditorConfig', this.model.sync, this.model);

Actually, strike that comment in #13. On further inspection, the intent is to bind the listenTo to the model, not the view. The event handler for this line refers to a method on the model, not the view.

BUT, there might be some extraneous code here. We don't need to bind the event handler to the object through an argument, which is what the fourth argument in these two lines would suggest:

// Push the active editor configuration to the textarea.
this.model.listenTo(this.model, 'change:activeEditorConfig', this.model.sync, this.model);
this.listenTo(this.model, 'change:isDirty', this.parseEditorDOM, this);

With listenTo, the handler is bound to the object that invokes listenTo.

[listenTo](http://backbonejs.org/#Events-listenTo): Tell an object to listen to a particular event on an other object...The callback will always be called with object as context.

Honestly, that quote from the docs is....damn muddled. Which object now? The object invoking listenTo or the one raising the event? Let's check the code in Backbone...

var listenMethods = {listenTo: 'on', listenToOnce: 'once'};

// Inversion-of-control versions of `on` and `once`. Tell *this* object to
// listen to an event in another object ... keeping track of what it's
// listening to.
_.each(listenMethods, function(implementation, method) {
  Events[method] = function(obj, name, callback) {
    var listeningTo = this._listeningTo || (this._listeningTo = {});
    var id = obj._listenId || (obj._listenId = _.uniqueId('l'));
    listeningTo[id] = obj;
    if (!callback && typeof name === 'object') callback = this;
    obj[implementation](name, callback, this);
    return this;
  };
});

So, the pertinent line is

obj[implementation](name, callback, this);

where implementation is on and this is the object that invoked listenTo.

The fourth argument passed to listenTo in the code changes above is never referenced in Backbone and just silently passes into the æther.

There's one more instance in EntityModel.js. I searched with the following regex:

listenTo\(.*,.*,.*,.*\)

Alright, this looks good! If this is going to create any issues (I don't think it will), I'd rather know them sooner rather than later.