backbone-helpers: extend Backbone natives with some convenience methods.

backbone-helper.js

// backbone-helpers: extend Backbone natives with some convenience methods 
// Implemented by overriding the extend function to modify the options passed into the original extend
// Adds the following methods:
//    Model.isDirty() -> check if a model has changed since the last sync with the server
//    Collection.getChangedSinceLastSave() -> return all the models that return true on isDirty()
//    Collection.saveAllChanged() -> save all the models returned by getChangedSinceLastSave()



(function (extend) {

    Backbone.Model.extend = function (opts) {

        opts.cleanAttributes = {};
        opts.clean = function () {
            this.cleanAttributes = _.clone(this.attributes);
        };
        opts.isDirty = function () {
            return !_.isEqual(this.cleanAttributes, this.attributes);
        };

        // Wrap initialize function to prevent overriding the user defined initialize
        var initialize = opts.initialize;
        opts.initialize = function () {

            if (initialize) {
                initialize.apply(this, arguments);
            }

            this.on("sync", function () {
                this.clean();
            });

            this.clean();
        };

        return extend.apply(this, arguments);
    };

})(Backbone.Model.extend);

(function (extend) {

    Backbone.Collection.extend = function (opts) {

        opts.getChangedSinceLastSave = function () {
            return this.filter(function (model) {
                return model.isDirty() || model.isNew();
            });
        };

        opts.saveAllChanged = function () {
            _.each(this.getChangedSinceLastSave(), function (model) {
                model.save();
            });
        };

        return extend.apply(this, arguments);
    };

})(Backbone.Collection.extend);

Backbone.LocalStorageView = Backbone.View.extend({
    localStoragePrefix: false,
    localStorage: false,
    storage: function (key, val) {

        if (typeof window.localStorage !== 'undefined') {
            this.localStorage = window.localStorage;
        }

        if (!this.localStoragePrefix) {
            return;
        }

        var localStorage = this.localStorage || {};
        var isSetting = typeof val !== "undefined";

        if (isSetting) {
            localStorage[this.localStoragePrefix + "." + key] = val;
        }
        else {
            return localStorage[this.localStoragePrefix + "." + key];
        }
    }
});