Function findRootContainerNode

code/composition/public/app.js:5934–5946

* Find the deepest React component completely containing the root of the * passed-in instance (for use when entire React trees are nested within each * other). If React trees are not nested, returns null.

(inst)

 * other). If React trees are not nested, returns null.
 */
function findRootContainerNode(inst) {
  // TODO: It may be a good idea to cache this to prevent unnecessary DOM
  // traversal, but caching is difficult to do correctly without using a
  // mutation observer to listen for all DOM changes.
  while (inst['return']) {
    inst = inst['return'];
  }
  if (inst.tag !== HostRoot) {
    // This can happen if we're in a detached tree.
    return null;
  }
  return inst.stateNode.containerInfo;
}

// Used to store ancestor hierarchy in top level callback
function getTopLevelCallbackBookKeeping(topLevelType, nativeEvent, targetInst) {