vault backup: 2022-04-26 17:12:42

React 的源码深入/React 的流程解析 - commit 阶段/React 的流程解析 - commit阶段.md

@@ -161,8 +161,29 @@ do {
 
 关于 commitLayoutEffects： [[React 的深入探索 - commitLayoutEffects]]
 
-结束三个循环之后 commit 阶段并没有结束，还会进入接下来逻辑
+结束三个循环之后 commit 阶段并没有结束，还会进入接下来的逻辑
 
 ```javascript
-
+var rootDidHavePassiveEffects = rootDoesHavePassiveEffects;
+
+if (rootDoesHavePassiveEffects) {
+	// 本次更新存在 useEffect
+	rootDoesHavePassiveEffects = false;
+	// 将 root 赋值给 rootWithPendingPassiveEffects，没错就是开头的循环
+	rootWithPendingPassiveEffects = root;
+	pendingPassiveEffectsLanes = lanes;
+	pendingPassiveEffectsRenderPriority = renderPriorityLevel;
+} else {
+	// 本次更新不存在 useEffect
+	nextEffect = firstEffect;
+	while (nextEffect !== null) {
+		var nextNextEffect = nextEffect.nextEffect;
+		// 循环设置为 null，目的是为了垃圾回收
+		nextEffect.nextEffect = null;
+		if (nextEffect.effectTag & Deletion) {
+			detachFiberAfterEffects(nextEffect);
+		}
+		nextEffect = nextNextEffect;
+	}
+}
 ```