Method firstChild

packages/router/src/utils/tree.ts:40–43

* @internal

(t: T)

   * @internal
   */
  firstChild(t: T): T | null {
    const n = findNode(t, this._root);
    return n && n.children.length > 0 ? n.children[0].value : null;
  }

  /**
   * @internal