import { isShadowRoot } from "./instanceOf.js"; export default function contains(parent, child) { var 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)) { var 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; }