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vue之生命周期

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<!DOCTYPE html>
<html>
<head>
    <title></title>
    <script type="text/javascript" src="https://cdn.jsdelivr.net/vue/2.1.3/vue.js"></script>
</head>
<body>

<div id="app">
     <p>{{ message }}</p>
</div>

<script type="text/javascript
"> var app = new Vue({ el: #app, data: { message : "xuxiao is boy" }, beforeCreate: function () { console.group(beforeCreate 創建前狀態===============》); console.log("%c%s", "color:red" , "el : " + this.$el); //undefined console.log("
%c%s", "color:red","data : " + this.$data); //undefined console.log("%c%s", "color:red","message: " + this.message) }, created: function () { console.group(created 創建完畢狀態===============》); console.log("%c%s", "color:red","el : " + this.$el); //
undefined console.log("%c%s", "color:red","data : " + this.$data); //已被初始化 console.log("%c%s", "color:red","message: " + this.message); //已被初始化 }, beforeMount: function () { console.group(beforeMount 掛載前狀態===============》); console.log("%c%s", "color:red","el : " + (this.$el)); //已被初始化 console.log(this.$el); console.log("%c%s", "color:red","data : " + this.$data); //已被初始化 console.log("%c%s", "color:red","message: " + this.message); //已被初始化 }, mounted: function () { console.group(mounted 掛載結束狀態===============》); console.log("%c%s", "color:red","el : " + this.$el); //已被初始化 console.log(this.$el); console.log("%c%s", "color:red","data : " + this.$data); //已被初始化 console.log("%c%s", "color:red","message: " + this.message); //已被初始化 }, beforeUpdate: function () { console.group(beforeUpdate 更新前狀態===============》); console.log("%c%s", "color:red","el : " + this.$el); console.log(this.$el); console.log("%c%s", "color:red","data : " + this.$data); console.log("%c%s", "color:red","message: " + this.message); }, updated: function () { console.group(updated 更新完成狀態===============》); console.log("%c%s", "color:red","el : " + this.$el); console.log(this.$el); console.log("%c%s", "color:red","data : " + this.$data); console.log("%c%s", "color:red","message: " + this.message); }, beforeDestroy: function () { console.group(beforeDestroy 銷毀前狀態===============》); console.log("%c%s", "color:red","el : " + this.$el); console.log(this.$el); console.log("%c%s", "color:red","data : " + this.$data); console.log("%c%s", "color:red","message: " + this.message); }, destroyed: function () { console.group(destroyed 銷毀完成狀態===============》); console.log("%c%s", "color:red","el : " + this.$el); console.log(this.$el); console.log("%c%s", "color:red","data : " + this.$data); console.log("%c%s", "color:red","message: " + this.message) } }) </script> </body> </html>

create 和 mounted 相關

咱們在chrome瀏覽器裏打開,F12console就能發現

  beforecreated:el 和 data 並未初始化
  created:完成了 data 數據的初始化,el沒有
  beforeMount:完成了 el 和 data 初始化
  mounted :完成掛載

另外在標紅處,我們能發現el還是 {{message}},這裏就是應用的 Virtual DOM(虛擬Dom)技術,先把坑占住了。到後面mounted掛載的時候再把值渲染進去。

destroy 相關

有關於銷毀,暫時還不是很清楚。我們在console裏執行下命令對 vue實例進行銷毀。銷毀完成後,我們再重新改變message的值,vue不再對此動作進行響應了。但是原先生成的dom元素還存在,可以這麽理解,執行了destroy操作,後續就不再受vue控制了。

生命周期總結

這麽多鉤子函數,我們怎麽用呢,我想大家可能有這樣的疑問吧,我也有,哈哈哈。

  beforecreate : 舉個栗子:可以在這加個loading事件
  created :在這結束loading,還做一些初始化,實現函數自執行
  mounted : 在這發起後端請求,拿回數據,配合路由鉤子做一些事情
  beforeDestory: 你確認刪除XX嗎? destoryed :當前組件已被刪除,清空相關內容

vue之生命周期