Question

I have a backbone model that looks somewhat like this:

var myModel = Backbone.Model.extend({
    watch : function() {
        this.watcher = setInterval("this.refetch", 5000);
    }

    refetch : function() {
        //do something
    }
});

The setInterval method doesn’t actually work, because, I suppose, this.refetch isn’t valid in the setInterval call. Neither does setInterval("refetch", 5000); work.

What I’m doing right now is this:

watch : function() {
    var that = this;
    setInterval(function(){
        that.refetch();
    }, 5000);   
}

Is there a better way to do this, so that I don’t need to use that.

Answer 1

Since Backbone already brings underscore.js with it, use it. In your case, context can be bound to interval function with _.bind:

setInterval( _.bind( function(){this.refetch();}, this), 5000);

This is better approach not only because it’s shorter, but also because it prevents that alias from beeing visible in nested scopes which can cause all sorts of hard-to-catch bugs. See idiomatic.js style guide, “Faces of this” section: https://github.com/rwldrn/idiomatic.js/