ReactSharedInternals() — react Function Reference

Source Code

packages/react-reconciler/src/ReactFiberTransition.js lines 79–130

ReactSharedInternals.S = function onStartTransitionFinishForReconciler(
  transition: Transition,
  returnValue: mixed,
) {
  markTransitionStarted();
  if (
    typeof returnValue === 'object' &&
    returnValue !== null &&
    typeof returnValue.then === 'function'
  ) {
    // If we're going to wait on some async work before scheduling an update.
    // We mark the time so we can later log how long we were blocked on the Action.
    // Ideally, we'd include the sync part of the action too but since that starts
    // in isomorphic code it currently leads to tricky layering. We'd have to pass
    // in performance.now() to this callback but we sometimes use a polyfill.
    startAsyncTransitionTimer();

    // This is an async action
    const thenable: Thenable<mixed> = (returnValue: any);
    entangleAsyncAction(transition, thenable);
  }
  if (enableViewTransition) {
    if (entangledTransitionTypes !== null) {
      // If we scheduled work on any new roots, we need to add any entangled async
      // transition types to those roots too.
      let root = firstScheduledRoot;
      while (root !== null) {
        queueTransitionTypes(root, entangledTransitionTypes);
        root = root.next;
      }
    }
    const transitionTypes = transition.types;
    if (transitionTypes !== null) {
      // Within this Transition we should've now scheduled any roots we have updates
      // to work on. If there are no updates on a root, then the Transition type won't
      // be applied to that root.
      let root = firstScheduledRoot;
      while (root !== null) {
        queueTransitionTypes(root, transitionTypes);
        root = root.next;
      }
      if (peekEntangledActionLane() !== NoLane) {
        // If we have entangled, async actions going on, the update associated with
        // these types might come later. We need to save them for later.
        entangleAsyncTransitionTypes(transitionTypes);
      }
    }
  }
  if (prevOnStartTransitionFinish !== null) {
    prevOnStartTransitionFinish(transition, returnValue);
  }
};