axe-core/lib/core/utils/contains.js

Accessibility engine for automated Web UI testing

/**
 * Wrapper for Node#contains; PhantomJS does not support Node#contains and erroneously reports that it does
 * @method contains
 * @memberof axe.utils
 * @param  {VirtualNode} vNode     The candidate container VirtualNode
 * @param  {VirtualNode} otherVNode The vNode to test is contained by `vNode`
 * @return {Boolean}           Whether `vNode` contains `otherVNode`
 */
axe.utils.contains = function(vNode, otherVNode) {
	/*eslint no-bitwise: 0*/
	'use strict';
	function containsShadowChild(vNode, otherVNode) {
		if (vNode.shadowId === otherVNode.shadowId) {
			return true;
		}
		return !!vNode.children.find(child => {
			return containsShadowChild(child, otherVNode);
		});
	}

	if (vNode.shadowId || otherVNode.shadowId) {
		return containsShadowChild(vNode, otherVNode);
	}

	if (vNode.actualNode) {
		if (typeof vNode.actualNode.contains === 'function') {
			return vNode.actualNode.contains(otherVNode.actualNode);
		}

		return !!(
			vNode.actualNode.compareDocumentPosition(otherVNode.actualNode) & 16
		);
	} else {
		// fallback for virtualNode only contexts (e.g. linting)
		// @see https://github.com/Financial-Times/polyfill-service/pull/183/files
		do {
			if (otherVNode === vNode) {
				return true;
			}
		} while ((otherVNode = otherVNode && otherVNode.parent));
	}

	return false;
};