| // Copyright 2021 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| /** |
| * Function to return the root node of a given node. |
| */ |
| export function getRootNode(node: Node): ShadowRoot|Document { |
| const potentialRoot = node.getRootNode(); |
| if (!(potentialRoot instanceof Document || potentialRoot instanceof ShadowRoot)) { |
| throw new Error(`Expected root of widget to be a document or shadowRoot, but was "${potentialRoot.nodeName}"`); |
| } |
| return potentialRoot; |
| } |
