Merge pull request Tencent#48 from aeroxy/master

将rewritePureUpdate内的update也promisify并且更新使用文档
cy-biggray · Nov 2, 2018 · 059f191 · 059f191
2 parents f8faa2f + 5fad49f
commit 059f191
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diff --git a/readme.md b/readme.md
@@ -57,7 +57,7 @@
 * 超小的代码尺寸(包括 json diff 共100多行)
 * 尊重且顺从小程序的设计(其他转译库相当于反其道行)
 * 增强 data 数据绑定，函数属性可直接绑定到 WXML
-* this.update 兼容 setData 同样的语法
+* this.update 和 setData 语法类似，但返回一个Promise
 * this.update 比原生 setData 的性能更优，更加智能
 * Westore 专为小程序插件开发[定制了模板](https://github.com/dntzhang/westore/tree/master/packages/westore-plugin)
 * Westore 集成了腾讯云开发
@@ -96,6 +96,25 @@ this.update({
 })
 ```
 
+和小程序的setData不同的是回调的方式，小程序的回调为setData的第二个入参，但是update则直接返回一个Promise，并且返回的数据内有更新的数据内容。例如：
+
+``` js
+this.setData({
+  motto: 'Hello Westore'
+}, () => {
+  console.log('the motto has been set')
+})
+```
+
+被改进为
+
+``` js
+this.store.data.mottto = 'Hello Westore'
+this.update().then(diff => {
+  console.log('the motto has been set', diff)
+})
+```
+
 这里需要特别强调，虽然 this.update 可以兼容小程序的 this.setData 的方式传参，但是更加智能，this.update 会先 Diff 然后 setData。原理:
 
 ![](./asset/update2.jpg)
@@ -295,6 +314,8 @@ this.setData({
   logs: (wx.getStorageSync('logs') || []).map(log => {
     return util.formatTime(new Date(log))
   })
+}, () => {
+  console.log('setData完成了')
 })
 ```
 
@@ -304,7 +325,10 @@ this.setData({
 this.store.data.logs = (wx.getStorageSync('logs') || []).map(log => {
   return util.formatTime(new Date(log))
 })
-this.update()
+this.update().then(diff => {
+  console.log('setData完成了')
+  console.log('更新内容为', diff)
+})
 ```
 
 看似一条语句变成了两条语句，但是 this.update 调用的 setData 是 diff 后的，所以传递的数据更少。

diff --git a/utils/create.js b/utils/create.js
@@ -124,24 +124,28 @@ function _arrayToPath(data, path, result) {
 function rewritePureUpdate(ctx) {
     ctx.update = function (patch) {
         const store = this.store
-        //defineFnProp(store.data)
-        if (patch) {
-            for (let key in patch) {
-                updateByPath(store.data, key, patch[key])
+        const that = this
+        return new Promise(resolve => {
+            //defineFnProp(store.data)
+            if (patch) {
+                for (let key in patch) {
+                    updateByPath(store.data, key, patch[key])
+                }
             }
-        }
-        let diffResult = diff(store.data, store.originData)
-        if (Object.keys(diffResult)[0] == '') {
-            diffResult = diffResult['']
-        }
-        if (Object.keys(diffResult).length > 0) {
-            this.setData(diffResult)
-            store.onChange && store.onChange(diffResult)
-            for (let key in diffResult) {
-                updateByPath(store.originData, key, typeof diffResult[key] === 'object' ? JSON.parse(JSON.stringify(diffResult[key])) : diffResult[key])
+            let diffResult = diff(store.data, store.originData)
+            let array = []
+            if (Object.keys(diffResult)[0] == '') {
+                diffResult = diffResult['']
             }
-        }
-        return diffResult
+            if (Object.keys(diffResult).length > 0) {
+                array.push( new Promise( cb => that.setData(diffResult, cb) ) )
+                store.onChange && store.onChange(diffResult)
+                for (let key in diffResult) {
+                    updateByPath(store.originData, key, typeof diffResult[key] === 'object' ? JSON.parse(JSON.stringify(diffResult[key])) : diffResult[key])
+                }
+            }
+            Promise.all(array).then( e => resolve(diffResult) )
+        })
     }
 }