Method find

packages/shell/src/model/node-children.ts:187–193

* 类似数组的 find * @param fn

(fn: (node: IPublicModelNode, index: number) => boolean)

   * @param fn
   */
  find(fn: (node: IPublicModelNode, index: number) => boolean): IPublicModelNode | null {
    return ShellNode.create(
      this[nodeChildrenSymbol].find((item: InnerNode, index: number) => {
        return fn(ShellNode.create(item)!, index);
      }),
    );
  }

  /**
   * 类似数组的 reduce