refactor(effectScope): restore scope after run

Author: posva

packages/reactivity/src/effectScope.ts

@@ -21,10 +21,6 @@ export class EffectScope {
    * removal
    */
   private index: number | undefined
-  /**
-   *  activeEffectScope in context not died should be recorded
-   */
-  private aliveEffectScope: EffectScope | undefined
 
   constructor(detached = false) {
     if (!detached && activeEffectScope) {
@@ -38,27 +34,24 @@ export class EffectScope {
 
   run<T>(fn: () => T): T | undefined {
     if (this.active) {
+      const currentEffectScope = activeEffectScope
       try {
-        this.aliveEffectScope = activeEffectScope
         activeEffectScope = this
         return fn()
       } finally {
-        activeEffectScope = this.aliveEffectScope
-        delete this.aliveEffectScope
+        activeEffectScope = currentEffectScope
       }
     } else if (__DEV__) {
       warn(`cannot run an inactive effect scope.`)
     }
   }
 
   on() {
-    this.aliveEffectScope = activeEffectScope
     activeEffectScope = this
   }
 
   off() {
-    activeEffectScope = this.aliveEffectScope
-    delete this.aliveEffectScope
+    activeEffectScope = this.parent
   }
 
   stop(fromParent?: boolean) {