Function performSyncWorkOnRoot

docs/external/js/react-dom.development.js:21861–21937

(root)

  function performSyncWorkOnRoot(root) {
    // Check if there's expired work on this root. Otherwise, render at Sync.
    var lastExpiredTime = root.lastExpiredTime;
    var expirationTime = lastExpiredTime !== NoWork ? lastExpiredTime : Sync;

    if (!((executionContext & (RenderContext | CommitContext)) === NoContext)) {
      {
        throw Error( "Should not already be working." );
      }
    }

    flushPassiveEffects(); // If the root or expiration time have changed, throw out the existing stack
    // and prepare a fresh one. Otherwise we'll continue where we left off.

    if (root !== workInProgressRoot || expirationTime !== renderExpirationTime$1) {
      prepareFreshStack(root, expirationTime);
      startWorkOnPendingInteractions(root, expirationTime);
    } // If we have a work-in-progress fiber, it means there's still work to do
    // in this root.


    if (workInProgress !== null) {
      var prevExecutionContext = executionContext;
      executionContext |= RenderContext;
      var prevDispatcher = pushDispatcher();
      var prevInteractions = pushInteractions(root);
      startWorkLoopTimer(workInProgress);

      do {
        try {
          workLoopSync();
          break;
        } catch (thrownValue) {
          handleError(root, thrownValue);
        }
      } while (true);

      resetContextDependencies();
      executionContext = prevExecutionContext;
      popDispatcher(prevDispatcher);

      {
        popInteractions(prevInteractions);
      }

      if (workInProgressRootExitStatus === RootFatalErrored) {
        var fatalError = workInProgressRootFatalError;
        stopInterruptedWorkLoopTimer();
        prepareFreshStack(root, expirationTime);
        markRootSuspendedAtTime(root, expirationTime);
        ensureRootIsScheduled(root);
        throw fatalError;
      }

      if (workInProgress !== null) {
        // This is a sync render, so we should have finished the whole tree.
        {
          {