Function processUpdateQueue

code/event-handlers/public/app.js:7324–7458

(current, workInProgress, queue, instance, props, renderExpirationTime)

}

function processUpdateQueue(current, workInProgress, queue, instance, props, renderExpirationTime) {
  if (current !== null && current.updateQueue === queue) {
    // We need to create a work-in-progress queue, by cloning the current queue.
    var currentQueue = queue;
    queue = workInProgress.updateQueue = {
      baseState: currentQueue.baseState,
      expirationTime: currentQueue.expirationTime,
      first: currentQueue.first,
      last: currentQueue.last,
      isInitialized: currentQueue.isInitialized,
      capturedValues: currentQueue.capturedValues,
      // These fields are no longer valid because they were already committed.
      // Reset them.
      callbackList: null,
      hasForceUpdate: false
    };
  }

  {
    // Set this flag so we can warn if setState is called inside the update
    // function of another setState.
    queue.isProcessing = true;
  }

  // Reset the remaining expiration time. If we skip over any updates, we'll
  // increase this accordingly.
  queue.expirationTime = NoWork;

  // TODO: We don't know what the base state will be until we begin work.
  // It depends on which fiber is the next current. Initialize with an empty
  // base state, then set to the memoizedState when rendering. Not super
  // happy with this approach.
  var state = void 0;
  if (queue.isInitialized) {
    state = queue.baseState;
  } else {
    state = queue.baseState = workInProgress.memoizedState;
    queue.isInitialized = true;
  }
  var dontMutatePrevState = true;
  var update = queue.first;
  var didSkip = false;
  while (update !== null) {
    var updateExpirationTime = update.expirationTime;
    if (updateExpirationTime > renderExpirationTime) {
      // This update does not have sufficient priority. Skip it.
      var remainingExpirationTime = queue.expirationTime;
      if (remainingExpirationTime === NoWork || remainingExpirationTime > updateExpirationTime) {
        // Update the remaining expiration time.
        queue.expirationTime = updateExpirationTime;
      }
      if (!didSkip) {
        didSkip = true;
        queue.baseState = state;
      }
      // Continue to the next update.
      update = update.next;
      continue;