From 896ae850781d340208ceada632d62b2e3226bc3d Mon Sep 17 00:00:00 2001
From: yuche <i@yuche.me>
Date: Mon, 3 Jun 2019 20:16:38 +0800
Subject: [PATCH] =?UTF-8?q?refactor(weapp):=20=E4=B8=A4=E6=96=B0=E7=94=9F?=
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---
 docs/apis/about/tarocomponent.md     | 4 +++-
 packages/taro-weapp/src/lifecycle.js | 8 ++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/docs/apis/about/tarocomponent.md b/docs/apis/about/tarocomponent.md
index 799e617bdf6..7f54fe038a4 100644
--- a/docs/apis/about/tarocomponent.md
+++ b/docs/apis/about/tarocomponent.md
@@ -80,7 +80,7 @@ class Welcome extends Component {
 constructor(props)
 ```
 
-React 组件的构造函数将会在装配之前被调用。当为一个 `Taro.Component` 子类定义构造函数时，你应该在任何其他的表达式之前调用 `super(props)`。否则，this.props 在构造函数中将是未定义，并可能引发异常。
+Taro 组件的构造函数将会在装配之前被调用。当为一个 `Taro.Component` 子类定义构造函数时，你应该在任何其他的表达式之前调用 `super(props)`。否则，this.props 在构造函数中将是未定义，并可能引发异常。
 
 构造函数是初始化状态的合适位置。若你不初始化状态且不绑定方法，那你也不需要为你的 Taro 组件定义一个构造函数。
 
@@ -88,6 +88,8 @@ React 组件的构造函数将会在装配之前被调用。当为一个 `Taro.C
 
 可以基于属性来初始化状态。这样有效地“分离（forks）”属性并根据初始属性设置状态。
 
+### 
+
 ### componentWillMount()
 
 ```jsx
diff --git a/packages/taro-weapp/src/lifecycle.js b/packages/taro-weapp/src/lifecycle.js
index 4fbf1f4cbca..b4a8e9fec6d 100644
--- a/packages/taro-weapp/src/lifecycle.js
+++ b/packages/taro-weapp/src/lifecycle.js
@@ -15,7 +15,8 @@ import { enqueueRender } from './render-queue'
 //   process.env.NODE_ENV !== 'production'
 
 function hasNewLifecycle (component) {
-  return isFunction(component.constructor.getDerivedStateFromProps)
+  const { getDerivedStateFromProps, getSnapshotBeforeUpdate } = component.constructor
+  return isFunction(getDerivedStateFromProps) || isFunction(getSnapshotBeforeUpdate)
 }
 
 function callGetDerivedStateFromProps (component, props, state) {
@@ -145,7 +146,6 @@ function doUpdate (component, prevProps, prevState) {
       Current.current = null
     }
   }
-  const snapshot = callGetSnapshotBeforeUpdate(component, prevProps, prevState)
 
   data = Object.assign({}, props, data)
   if (component.$usedState && component.$usedState.length) {
@@ -171,6 +171,10 @@ function doUpdate (component, prevProps, prevState) {
 
   const dataDiff = diffObjToPath(data, component.$scope.data)
   const __mounted = component.__mounted
+  let snapshot
+  if (__mounted) {
+    snapshot = callGetSnapshotBeforeUpdate(component, prevProps, prevState)
+  }
 
   // 每次 setData 都独立生成一个 callback 数组
   let cbs = []