deferHiddenOffscreenComponent() — react Function Reference

Source Code

packages/react-reconciler/src/ReactFiberBeginWork.js lines 826–870

function deferHiddenOffscreenComponent(
  current: Fiber | null,
  workInProgress: Fiber,
  nextBaseLanes: Lanes,
  renderLanes: Lanes,
  remainingChildLanes: Lanes,
) {
  const nextState: OffscreenState = {
    baseLanes: nextBaseLanes,
    // Save the cache pool so we can resume later.
    cachePool: getOffscreenDeferredCache(),
  };
  workInProgress.memoizedState = nextState;
  // push the cache pool even though we're going to bail out
  // because otherwise there'd be a context mismatch
  if (current !== null) {
    pushTransition(workInProgress, null, null);
  }

  // We're about to bail out, but we need to push this to the stack anyway
  // to avoid a push/pop misalignment.
  reuseHiddenContextOnStack(workInProgress);

  pushOffscreenSuspenseHandler(workInProgress);

  if (current !== null) {
    // Since this tree will resume rendering in a separate render, we need
    // to propagate parent contexts now so we don't lose track of which
    // ones changed.
    propagateParentContextChangesToDeferredTree(
      current,
      workInProgress,
      renderLanes,
    );
  }

  // We override the remaining child lanes to be the subset that we computed
  // on the outside. We need to do this after propagating the context
  // because propagateParentContextChangesToDeferredTree may schedule
  // work which bubbles all the way up to the root and updates our child lanes.
  // We want to dismiss that since we're not going to work on it yet.
  workInProgress.childLanes = remainingChildLanes;

  return null;
}