Function flushSync

docs/external/js/react-dom.development.js:22048–22069

(fn, a)

    }
  }
  function flushSync(fn, a) {
    if ((executionContext & (RenderContext | CommitContext)) !== NoContext) {
      {
        {
          throw Error( "flushSync was called from inside a lifecycle method. It cannot be called when React is already rendering." );
        }
      }
    }

    var prevExecutionContext = executionContext;
    executionContext |= BatchedContext;

    try {
      return runWithPriority$1(ImmediatePriority, fn.bind(null, a));
    } finally {
      executionContext = prevExecutionContext; // Flush the immediate callbacks that were scheduled during this batch.
      // Note that this will happen even if batchedUpdates is higher up
      // the stack.

      flushSyncCallbackQueue();
    }
  }

  function prepareFreshStack(root, expirationTime) {
    root.finishedWork = null;