Add Events#oneTimeListenTo

backbone.js

@@ -218,6 +218,20 @@
     }
   };
 
+  var listenMethods = {listenTo: 'on', listenToOnce: 'once'};
+
+  // An 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(eventBinder, method) {
+    Events[method] = function(object, events, callback) {
+      var listeners = this._listeners || (this._listeners = {});
+      var id = obj._listenerId || (obj._listenerId = _.uniqueId('l'));
+      listeners[id] = obj;
+      obj[eventBinder](name, typeof name === 'object' ? this : callback, this);
+      return this;
+    };
+  });
+
   // Aliases for backwards compatibility.
   Events.bind   = Events.on;
   Events.unbind = Events.off;