Method query

packages/core/src/debug/debug_node.ts:320–323

* @returns the first `DebugElement` that matches the predicate at any depth in the subtree.

(predicate: Predicate<DebugElement>)

   * @returns the first `DebugElement` that matches the predicate at any depth in the subtree.
   */
  query(predicate: Predicate<DebugElement>): DebugElement {
    const results = this.queryAll(predicate);
    return results[0] || null;
  }

  /**
   * @returns All `DebugElement` matches for the predicate at any depth in the subtree.