Function flushPassiveEffects

packages/react-reconciler/src/ReactFiberWorkLoop.js:4452–4487

()

}

function flushPassiveEffects(): boolean {
  if (pendingEffectsStatus !== PENDING_PASSIVE_PHASE) {
    return false;
  }
  // TODO: Merge flushPassiveEffectsImpl into this function. I believe they were only separate
  // in the first place because we used to wrap it with
  // `Scheduler.runWithPriority`, which accepts a function. But now we track the
  // priority within React itself, so we can mutate the variable directly.
  // Cache the root since pendingEffectsRoot is cleared in
  // flushPassiveEffectsImpl
  const root = pendingEffectsRoot;
  // Cache and clear the remaining lanes flag; it must be reset since this
  // method can be called from various places, not always from commitRoot
  // where the remaining lanes are known
  const remainingLanes = pendingEffectsRemainingLanes;
  pendingEffectsRemainingLanes = NoLanes;

  const renderPriority = lanesToEventPriority(pendingEffectsLanes);
  const priority = lowerEventPriority(DefaultEventPriority, renderPriority);
  const prevTransition = ReactSharedInternals.T;
  const previousPriority = getCurrentUpdatePriority();

  try {
    setCurrentUpdatePriority(priority);
    ReactSharedInternals.T = null;
    return flushPassiveEffectsImpl();
  } finally {
    setCurrentUpdatePriority(previousPriority);
    ReactSharedInternals.T = prevTransition;

    // Once passive effects have run for the tree - giving components a
    // chance to retain cache instances they use - release the pooled
    // cache at the root (if there is one)
    releaseRootPooledCache(root, remainingLanes);
  }
}

function flushPassiveEffectsImpl() {
  // Cache and clear the transitions flag