From 0e921b9b78e452da78f09f11edb964f5f21fd572 Mon Sep 17 00:00:00 2001
From: guaijie <30885718+guaijie@users.noreply.github.com>
Date: Sat, 22 Feb 2020 00:07:08 +0800
Subject: [PATCH 1/3] Update effect.ts

---
 packages/reactivity/src/effect.ts | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/packages/reactivity/src/effect.ts b/packages/reactivity/src/effect.ts
index c0f4707d83d..d4c327efc42 100644
--- a/packages/reactivity/src/effect.ts
+++ b/packages/reactivity/src/effect.ts
@@ -176,17 +176,19 @@ export function trigger(
   }
   const effects = new Set<ReactiveEffect>()
   const computedRunners = new Set<ReactiveEffect>()
-  if (
-    type === TriggerOpTypes.CLEAR ||
-    (key === 'length' &&
-      isArray(target) &&
-      (newValue as number) < (oldValue as number))
-  ) {
+  if (type === TriggerOpTypes.CLEAR) {
     // collection being cleared or Array length mutation
     // trigger all effects for target
-    depsMap.forEach(dep => {
+    depsMap.forEach((dep, i) => {
       addRunners(effects, computedRunners, dep)
     })
+  } else if (key === 'length' && isArray(target)) {
+    const startIndex: number = (newValue as number) || 0
+    depsMap.forEach((dep, i) => {
+      if (i >= startIndex || i === 'length') {
+        addRunners(effects, computedRunners, dep)
+      }
+    })
   } else {
     // schedule runs for SET | ADD | DELETE
     if (key !== void 0) {

From 64dc675f6404d6c6882b4da9e22e977e8a32e30f Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Sat, 22 Feb 2020 05:08:59 +0100
Subject: [PATCH 2/3] Update effect.ts

---
 packages/reactivity/src/effect.ts | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/packages/reactivity/src/effect.ts b/packages/reactivity/src/effect.ts
index d4c327efc42..8f81efd9b90 100644
--- a/packages/reactivity/src/effect.ts
+++ b/packages/reactivity/src/effect.ts
@@ -177,15 +177,14 @@ export function trigger(
   const effects = new Set<ReactiveEffect>()
   const computedRunners = new Set<ReactiveEffect>()
   if (type === TriggerOpTypes.CLEAR) {
-    // collection being cleared or Array length mutation
+    // collection being cleared
     // trigger all effects for target
-    depsMap.forEach((dep, i) => {
+    depsMap.forEach(dep => {
       addRunners(effects, computedRunners, dep)
     })
   } else if (key === 'length' && isArray(target)) {
-    const startIndex: number = (newValue as number) || 0
-    depsMap.forEach((dep, i) => {
-      if (i >= startIndex || i === 'length') {
+    depsMap.forEach((dep, key) => {
+      if (key === 'length' || key > (newValue as number)) {
         addRunners(effects, computedRunners, dep)
       }
     })

From 9f49b1b00d6c8f70af598bfa8f643a5dc44f7e24 Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Sat, 22 Feb 2020 05:09:54 +0100
Subject: [PATCH 3/3] Update effect.ts

---
 packages/reactivity/src/effect.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/reactivity/src/effect.ts b/packages/reactivity/src/effect.ts
index 8f81efd9b90..010aea0020a 100644
--- a/packages/reactivity/src/effect.ts
+++ b/packages/reactivity/src/effect.ts
@@ -184,7 +184,7 @@ export function trigger(
     })
   } else if (key === 'length' && isArray(target)) {
     depsMap.forEach((dep, key) => {
-      if (key === 'length' || key > (newValue as number)) {
+      if (key === 'length' || key >= (newValue as number)) {
         addRunners(effects, computedRunners, dep)
       }
     })