message: ts: optimize type infer in util.each when iterate on an interface.
diff: @@ -24,7 +24,7 @@ import Storage from '../Storage';
  import { MatrixArray } from '../core/matrix';
  import Displayable from '../graphic/Displayable';
  -export interface GroupOption extends ElementProps {
  +export interface GroupProps extends ElementProps {
  }
  export default class Group extends Element {
  @@ -37,7 +37,7 @@ export default class Group extends Element {
  __storage: Storage
  - constructor(opts?: GroupOption) {
  + constructor(opts?: GroupProps) {
  super();
  this.attr(opts);
  