Function createRootImpl

docs/external/js/react-dom.development.js:24757–24770

(container, tag, options)

  };

  function createRootImpl(container, tag, options) {
    // Tag is either LegacyRoot or Concurrent Root
    var hydrate = options != null && options.hydrate === true;
    var hydrationCallbacks = options != null && options.hydrationOptions || null;
    var root = createContainer(container, tag, hydrate);
    markContainerAsRoot(root.current, container);

    if (hydrate && tag !== LegacyRoot) {
      var doc = container.nodeType === DOCUMENT_NODE ? container : container.ownerDocument;
      eagerlyTrapReplayableEvents(container, doc);
    }

    return root;
  }
  function createLegacyRoot(container, options) {
    return new ReactDOMBlockingRoot(container, LegacyRoot, options);
  }