Function findHostSubtreeRoot

packages/react-reconciler/src/commitWork.ts:113–167

(
	finishedWork: FiberNode,
	callback: (hostSubtreeRoot: FiberNode) => void
)

// 寻找根host节点，考虑到Fragment，可能存在多个
function findHostSubtreeRoot(
	finishedWork: FiberNode,
	callback: (hostSubtreeRoot: FiberNode) => void
) {
	let hostSubtreeRoot = null;
	let node = finishedWork;
	while (true) {
		if (node.tag === HostComponent) {
			if (hostSubtreeRoot === null) {
				// 还未发现 root，当前就是
				hostSubtreeRoot = node;
				callback(node);
			}
		} else if (node.tag === HostText) {
			if (hostSubtreeRoot === null) {
				// 还未发现 root，text可以是顶层节点
				callback(node);
			}
		} else if (
			node.tag === OffscreenComponent &&
			node.pendingProps.mode === 'hidden' &&
			node !== finishedWork
		) {
			// 隐藏的OffscreenComponent跳过
		} else if (node.child !== null) {
			node.child.return = node;
			node = node.child;
			continue;
		}

		if (node === finishedWork) {
			return;
		}

		while (node.sibling === null) {
			if (node.return === null || node.return === finishedWork) {
				return;
			}

			if (hostSubtreeRoot === node) {
				hostSubtreeRoot = null;
			}

			node = node.return;
		}

		// 去兄弟节点寻找，此时当前子树的host root可以移除了
		if (hostSubtreeRoot === node) {
			hostSubtreeRoot = null;
		}

		node.sibling.return = node.return;
		node = node.sibling;
	}
}

function hideOrUnhideAllChildren(finishedWork: FiberNode, isHidden: boolean) {
	findHostSubtreeRoot(finishedWork, (hostRoot) => {