Function performSyncWorkOnRoot

lib/assets/react-source/development/react.js:25421–25497

(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.
	      {
	        {