message: refactor: use object spread operator rather than merge
diff: @@ -24,18 +24,3 @@ export function isObservable(obj: any | Observable<any>): obj is Observable<any>
  // TODO use Symbol.observable when https://github.com/ReactiveX/rxjs/issues/2415 will be resolved
  return !!obj && typeof obj.subscribe === 'function';
  }
  -
  -// TODO(misko): replace with Object.assign once we require ES6.
  -export function merge<V>(m1: {[key: string]: V}, m2: {[key: string]: V}): {[key: string]: V} {
  - const m: {[key: string]: V} = {};
  -
  - for (const k of Object.keys(m1)) {
  - m[k] = m1[k];
  - }
  -
  - for (const k of Object.keys(m2)) {
  - m[k] = m2[k];
  - }
  -
  - return m;
  -}
  