soomla-blog.backbone.complex.snippet-3.js

var BackboneViewExtensions = {

    mixin : function(from) {
        var to = this.prototype;

        // we add those methods which exists on `from` but not on `to` to the latter
        _.defaults(to, from);

        // ...and we do the same for events and triggers
        _.defaults(to.events, from.events);
        _.defaults(to.triggers, from.triggers);

        // we then extend `to`'s `initialize`
        BackboneExtensions.extendMethod(to, from, "initialize");
        
        // … and its `render`
        Utils.extendMethod(to, from, "render");
    },

    // Helper method to extend an already existing method
    extendMethod : function(to, from, methodName) {

        // if the method is defined on from ...
        if (!_.isUndefined(from[methodName])) {
            var old = to[methodName];

            // ... we create a new function on to
            to[methodName] = function() {

                // wherein we first call the method which exists on `to`
                var oldReturn = old.apply(this, arguments);

                // and then call the method on `from`
                from[methodName].apply(this, arguments);

                // and then return the expected result,
                // i.e. what the method on `to` returns
                return oldReturn;
            };
        }
    }
};
_.extend(Backbone.View.prototype, BackboneViewExtensions);