text: 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;
  }