Function renderRootConcurrent

packages/react-reconciler/src/ReactFiberWorkLoop.js:2688–2962

(root: FiberRoot, lanes: Lanes)

}

function renderRootConcurrent(root: FiberRoot, lanes: Lanes): RootExitStatus {
  const prevExecutionContext = executionContext;
  executionContext |= RenderContext;
  const prevDispatcher = pushDispatcher(root.containerInfo);
  const prevAsyncDispatcher = pushAsyncDispatcher();

  // If the root or lanes have changed, throw out the existing stack
  // and prepare a fresh one. Otherwise we'll continue where we left off.
  if (workInProgressRoot !== root || workInProgressRootRenderLanes !== lanes) {
    if (enableUpdaterTracking) {
      if (isDevToolsPresent) {
        const memoizedUpdaters = root.memoizedUpdaters;
        if (memoizedUpdaters.size > 0) {
          restorePendingUpdaters(root, workInProgressRootRenderLanes);
          memoizedUpdaters.clear();
        }

        // At this point, move Fibers that scheduled the upcoming work from the Map to the Set.
        // If we bailout on this work, we'll move them back (like above).
        // It's important to move them now in case the work spawns more work at the same priority with different updaters.
        // That way we can keep the current update and future updates separate.
        movePendingFibersToMemoized(root, lanes);
      }
    }

    workInProgressTransitions = getTransitionsForLanes(root, lanes);

    resetRenderTimer();
    prepareFreshStack(root, lanes);
  } else {
    // This is a continuation of an existing work-in-progress.
    //
    // If we were previously in prerendering mode, check if we received any new
    // data during an interleaved event.
    workInProgressRootIsPrerendering = checkIfRootIsPrerendering(root, lanes);
  }

  if (enableSchedulingProfiler) {
    markRenderStarted(lanes);
  }

  outer: do {
    try {
      if (
        workInProgressSuspendedReason !== NotSuspended &&
        workInProgress !== null
      ) {
        // The work loop is suspended. We need to either unwind the stack or
        // replay the suspended component.
        const unitOfWork = workInProgress;
        const thrownValue = workInProgressThrownValue;
        resumeOrUnwind: switch (workInProgressSuspendedReason) {
          case SuspendedOnError: {
            // Unwind then continue with the normal work loop.
            workInProgressSuspendedReason = NotSuspended;
            workInProgressThrownValue = null;
            throwAndUnwindWorkLoop(
              root,