Use ajax's "then" instead of {success:...,error:...}

This allows for implementors of ajax functions to not need to look for
success, error callbacks in their options.

Author: mbjorkegren

backbone.js

@@ -1242,19 +1242,20 @@
       };
     }
 
-    // Pass along `textStatus` and `errorThrown` from jQuery.
-    var error = options.error;
-    options.error = function(xhr, textStatus, errorThrown) {
-      options.textStatus = textStatus;
-      options.errorThrown = errorThrown;
-      if (error) error.apply(this, arguments);
-    };
-
     // Allow one-time override of the ajax function.
     var ajax = options.ajax || Backbone.ajax;
 
     // Make the request, allowing the user to override any Ajax options.
     var xhr = options.xhr = ajax(_.extend(params, options));
+
+    var error = options.error;
+    xhr.then(options.success, function(xhr, textStatus, errorThrown) {
+      // Pass along `textStatus` and `errorThrown` from jQuery.
+      options.textStatus = textStatus;
+      options.errorThrown = errorThrown;
+      if (error) error.apply(this, arguments);
+    });
+
     model.trigger('request', model, xhr, options);
     return xhr;
   };

test/collection.js

@@ -784,7 +784,7 @@
   test("#1412 - Trigger 'request' and 'sync' events.", 4, function() {
     var collection = new Backbone.Collection;
     collection.url = '/test';
-    Backbone.ajax = function(settings){ settings.success(); };
+    Backbone.ajax = function(settings){ return $.Deferred().resolve(); };
 
     collection.on('request', function(obj, xhr, options) {
       ok(obj === collection, "collection has correct 'request' event after fetching");
@@ -1151,8 +1151,9 @@
     }));
     var ajax = Backbone.ajax;
     Backbone.ajax = function (params) {
-      _.defer(params.success);
-      return {someHeader: 'headerValue'};
+      var dfd = $.Deferred();
+      _.defer(dfd.resolve);
+      return $.extend({someHeader: 'headerValue'}, dfd);
     };
     collection.fetch({
       success: function () { start(); }

test/environment.js

@@ -17,6 +17,7 @@
     // Capture ajax settings for comparison.
     Backbone.ajax = function(settings) {
       env.ajaxSettings = settings;
+      return $.Deferred();
     };
 
     // Capture the arguments to Backbone.sync for comparison.
@@ -26,7 +27,7 @@
         model: model,
         options: options
       };
-      sync.apply(this, arguments);
+      return sync.apply(this, arguments);
     };
 
   });

test/sync.js

@@ -147,6 +147,7 @@
   test("Backbone.ajax", 1, function() {
     Backbone.ajax = function(settings){
       strictEqual(settings.url, '/test');
+      return $.Deferred();
     };
     var model = new Backbone.Model();
     model.url = '/test';
@@ -214,8 +215,8 @@
       strictEqual(options.textStatus, 'textStatus');
       strictEqual(options.errorThrown, 'errorThrown');
     });
-    model.fetch();
-    this.ajaxSettings.error({}, 'textStatus', 'errorThrown');
+    var rawDeferred = model.fetch();
+    rawDeferred.reject(rawDeferred, 'textStatus', 'errorThrown');
   });
 
 })();