A simple snapshot extension for Backbone models written mainly to introduce a rollback() feature

backbone.snapnroll.js

_.extend(Backbone.Model.prototype, {
  /**
   * Copy current attributes and store it in a private property
   * 
   * @returns Model Instance
   * @type Object
   */
  createSnapshot: function () {
    this._snapshot = _.clone(this.attributes);
    return this;
  },

  /**
   * Clear the snapshot property (assign empty hash)
   * 
   * @returns Model Instance
   * @type Object
   */
  resetSnapshot: function () {
    this._snapshot = {};
    return this;
  },

  /**
   * Return the current snapshot (shallow copy)
   * 
   * @returns Snapshot Hash
   * @type Object
   */
  snapshot: function () {
    if (_.isUndefined(this._snapshot)) {
      this.resetSnapshot();
    }
    return _.clone(this._snapshot);
  },
  
  /**
   * Replace the current model contents with the latest snapshot
   * 
   * @uses Model.set()
   * @returns Model Instance
   * @type Object
   */
  rollback: function () {
    if (_.isEmpty(this._snapshot) === false) {
      this.set(this._snapshot);
    }
    this.resetSnapshot();
    return this;
  }
});

example-usage.js

var test = new Backbone.Model({
  name:'mike'
});

test.snapshot();
// >> Object {}

test.createSnapshot().snapshot();
// >> Object {name: "mike"}

test.set('name', 'jim');
// Backbone.Model {cid: "c1", attributes: Object, _changing: false, _previousAttributes: Object, changed: Object…}

test.snapshot();
// >> Object {name: "mike"}

test.attributes
// >> Object {name: "jim"}

test.rollback().attributes
// >> Object {name: "mike"}