Method changes

modules/core/EditSystem.js:748–762

* changes * This returns a summery of all changes made from `base` -> `stable` * Optionally includes a given action function to apply to the `stable` graph. * @param {Function?} action - Optional action to apply to the `stable` graph * @return {Object} Object containing `modified`,

(action)

   * @return {Object}     Object containing `modified`, `created`, `deleted` summary of changes
   */
  changes(action) {
    let difference = this._fullDifference;

    if (action) {
      const base = this.base.graph;
      const head = action(this.stable.graph);
      difference = new Difference(base, head);
    }

    return {
      created:  difference.created(),
      modified: difference.modified(),
      deleted:  difference.deleted()
    };
  }


  /**