Function performConcurrentWorkOnRoot

packages/react-reconciler/src/workLoop.ts:172–218

(
	root: FiberRootNode,
	didTimeout: boolean
)

}

function performConcurrentWorkOnRoot(
	root: FiberRootNode,
	didTimeout: boolean
): any {
	// 保证useEffect回调执行
	const curCallback = root.callbackNode;
	const didFlushPassiveEffect = flushPassiveEffects(root.pendingPassiveEffects);
	if (didFlushPassiveEffect) {
		if (root.callbackNode !== curCallback) {
			return null;
		}
	}

	const lane = getNextLane(root);
	const curCallbackNode = root.callbackNode;
	if (lane === NoLane) {
		return null;
	}
	const needSync = lane === SyncLane || didTimeout;
	// render阶段
	const exitStatus = renderRoot(root, lane, !needSync);

	switch (exitStatus) {
		// 中断
		case RootInComplete:
			if (root.callbackNode !== curCallbackNode) {
				return null;
			}
			return performConcurrentWorkOnRoot.bind(null, root);
		case RootCompleted:
			const finishedWork = root.current.alternate;
			root.finishedWork = finishedWork;
			root.finishedLane = lane;
			wipRootRenderLane = NoLane;
			commitRoot(root);
			break;
		case RootDidNotComplete:
			markRootSuspended(root, lane);
			wipRootRenderLane = NoLane;
			ensureRootIsScheduled(root);
			break;
		default:
			if (__DEV__) {
				console.error('还未实现的并发更新结束状态');
			}
	}
}

function performSyncWorkOnRoot(root: FiberRootNode) {
	const nextLane = getNextLane(root);