26 lines
697 B
Text
26 lines
697 B
Text
|
// @flow
|
||
|
import { isShadowRoot } from './instanceOf';
|
||
|
|
||
|
export default function contains(parent: Element, child: Element) {
|
||
|
const rootNode = child.getRootNode && child.getRootNode();
|
||
|
|
||
|
// First, attempt with faster native method
|
||
|
if (parent.contains(child)) {
|
||
|
return true;
|
||
|
}
|
||
|
// then fallback to custom implementation with Shadow DOM support
|
||
|
else if (rootNode && isShadowRoot(rootNode)) {
|
||
|
let next = child;
|
||
|
do {
|
||
|
if (next && parent.isSameNode(next)) {
|
||
|
return true;
|
||
|
}
|
||
|
// $FlowFixMe[prop-missing]: need a better way to handle this...
|
||
|
next = next.parentNode || next.host;
|
||
|
} while (next);
|
||
|
}
|
||
|
|
||
|
// Give up, the result is false
|
||
|
return false;
|
||
|
}
|