I have the following code:
var GoalPanelView = Backbone.View.extend({
// Bind to the goal panel DOM element
el: $("#sidebar-goals"),
// Initialize the collection
initialize: function() {
this.collection = Goals;
this.collection.bind('add', this.appendItem);
},
// Create a new goal when a user presses enter in the enter goal input
createOnEnter: function(e) {
if (e.keyCode != 13) return;
this.addItem();
//Goals.create(this.newAttributes());
},
// Add the goal item to the goal list
addItem: function() {
var goal = new Goal();
goal.set(this.newAttributes());
var goalsElem = this.el;
this.collection.add(goal);
$(this.el).children("#enter-goal").val('');
},
// Append DOM element to the parent el
appendItem: function(item) {
var goalView = new GoalView({
model: item,
});
$(this.elem).append(goalView.render().el);
}
});
My problem is inside of the appendItem function. When I use this inside of the appendItem function, I believe that it thinks that the this refers to the this.collection rather than the GoalPanelView. How would I get the this to refer to the GoalPanelView rather than the collection? I tried to pass another variable into the appendItem function which held the contents of this.elem, but it didn't seem to work.
One thing that worked was when I moved the appendItem function into the collection and changed the initialization to bind to this.collection.bind('add', appendItem); but I do not want to put the view stuff into the collection logic.
You can add a scope when binding an event handler, like so:
this.collection.bind('add', this.appendItem, this);
The scope sets the value of this inside the handler. In you case, the current object.
Edit: Javascript Garden has a great explaination why this.appendItem does not actually carry the scope of the function itself, it's just a function pointer, not a method pointer. One of the quirks of Javascript..