Merge pull request Meituan-Dianping#493 from jkzing/improve-nc

aOrz · web-flow · commit 75c67366fc70 · 2018-05-17T11:43:57.000+08:00
fix: properties could be empty
diff --git a/src/platforms/mp/runtime/lifecycle.js b/src/platforms/mp/runtime/lifecycle.js
@@ -40,8 +40,11 @@ function getGlobalData (app, rootVueVM) {
   }
 }
 
+/**
+ * 格式化 properties 属性，并给每个属性加上 observer 方法
+ */
 function normalizeProperties (vm) {
-  const properties = vm.$options.properties
+  const properties = vm.$options.properties || {}
   const res = {}
   let val
   for (const key in properties) {
@@ -52,7 +55,7 @@ function normalizeProperties (vm) {
       type: val.type,
       value: val.value,
       observer (newVal, oldVal) {
-        vm[key] = newVal
+        vm[key] = newVal // 先修改值再触发原始的 observer，跟 watch 行为保持一致
         if (typeof val.observer === 'function') {
           val.observer.call(vm, newVal, oldVal)
         }
@@ -62,14 +65,17 @@ function normalizeProperties (vm) {
   return res
 }
 
+/**
+ * 把 properties 中的属性 proxy 到 vm 上
+ */
 function initMpProps (vm) {
   const mpProps = vm._mpProps = {}
   const keys = Object.keys(vm.$options.properties || {})
   keys.forEach(key => {
     if (!(key in vm)) {
       proxy(vm, '_mpProps', key)
+      mpProps[key] = undefined // for observe
     }
-    mpProps[key] = undefined // for observe
   })
   observe(mpProps, true)
 }
@@ -140,8 +146,9 @@ export function initMP (mpType, next) {
     initMpProps(rootVueVM)
 
     global.Component({
-      // 页面的初始数据
+      // 小程序原生的组件属性
       properties: normalizeProperties(rootVueVM),
+      // 页面的初始数据
       data: {
         $root: {}
       },
