@ckeditor/ckeditor5-utils/src/dom/getcommonancestor.js

Miscellaneous utilities used by CKEditor 5.

/**
 * @license Copyright (c) 2003-2025, CKSource Holding sp. z o.o. All rights reserved.
 * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-licensing-options
 */
/**
 * @module utils/dom/getcommonancestor
 */
import { getAncestors } from './getancestors.js';
/**
 * Searches and returns the lowest common ancestor of two given nodes.
 *
 * @param nodeA First node.
 * @param nodeB Second node.
 * @returns Lowest common ancestor of both nodes or `null` if nodes do not have a common ancestor.
 */
export function getCommonAncestor(nodeA, nodeB) {
    const ancestorsA = getAncestors(nodeA);
    const ancestorsB = getAncestors(nodeB);
    let i = 0;
    // It does not matter which array is shorter.
    while (ancestorsA[i] == ancestorsB[i] && ancestorsA[i]) {
        i++;
    }
    return i === 0 ? null : ancestorsA[i - 1];
}