text: export const obj = {
      changedAttributes: function(diff) {
          if (!diff) return !!this.hasChanged() && _.clone(this.changed);
          var val, changed = !1, old = this._changing ? this._previousAttributes : this.attributes;
          for(var attr in diff)_.isEqual(old[attr], val = diff[attr]) || ((changed || (changed = {}))[attr] = val);
          return changed;
      }
  };
  