Vue#1.0和#2.0生命周期详解
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1.0 生命周期
image- 2.0 生命周期
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两个版本对比
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vue的生命周期各阶段都做了什么？
beforeCreate 实例创建前：这个阶段实例的data、methods是读不到的
created 实例创建后：这个阶段已经完成了数据观测(dataobserver)，属性和方法的运算，watch/event 事件回调。mount挂载阶段还没开始，$el属性目前不可见，数据并没有在DOM元素上进行渲染
beforeMount：在挂载开始之前被调用：相关的 render 函数首次被调用。
mounted：el选项的DOM节点被新创建的vm.$el替换，并挂载到实例上去之后调用此生命周期函数。此时实例的数据在DOM节点上进行渲染
beforeUpdate：数据更新时调用，但不进行DOM重新渲染，在数据更新时DOM没渲染前可以在这个生命函数里进行状态处理
updated：这个状态下数据更新并且DOM重新渲染，当这个生命周期函数被调用时，组件 DOM 已经更新，所以你现在可以执行依赖于 DOM 的操作。当实例每次进行数据更新时updated都会执行
beforeDestory：实例销毁之前调用。
destroyed：Vue 实例销毁后调用。调用后，Vue 实例指示的所有东西都会解绑定，所有的事件监听器会被移除，所有的子实例也会被销毁。
<!DOCTYPE html>
<html>
<head>
<title>钩子函数</title>
<script type="text/javascript" src="vue_2.2.4.js"></script>
<body>
<div id="app">
<p>{{ message }}</p>
<input type="button" @click="change" value="更新数据" />
<input type="button" @click="destroy" value="销毁" />
</div>
<script type="text/javascript">
var vm = new Vue({
el: '#app',
data: {
message : "Welcome Vue"
},
methods:{
change() {
this.message = 'Datura is me';
},
destroy() {
vm.$destroy();
}
},
beforeCreate: function () {
console.group('beforeCreate 创建前状态===============》');
console.log("%c%s", "color:red","el : " + this.$el); //undefined
console.log("%c%s", "color:red","data : " + this.$data); //undefined
console.log("%c%s", "color:red","message: " + this.message);//undefined
},
created: function () {
console.group('created 创建完毕状态===============》');
console.log("%c%s", "color:red","el : " + this.$el); //undefined
console.log("%c%s", "color:green","data : " + this.$data); //[object Object] => 已被初始化
console.log("%c%s", "color:green","message: " + this.message); //Welcome Vue => 已被初始化
},
beforeMount: function () {
console.group('beforeMount 挂载前状态===============》');
console.log("%c%s", "color:green","el : " + (this.$el)); //已被初始化
console.log(this.$el); // 当前挂在的元素
console.log("%c%s", "color:green","data : " + this.$data); //已被初始化
console.log("%c%s", "color:green","message: " + this.message); //已被初始化
},
mounted: function () {
console.group('mounted 挂载结束状态===============》');
console.log("%c%s", "color:green","el : " + this.$el); //已被初始化
console.log(this.$el);
console.log("%c%s", "color:green","data : " + this.$data); //已被初始化
console.log("%c%s", "color:green","message: " + this.message); //已被初始化
},
beforeUpdate: function () {
alert("更新前状态");
console.group('beforeUpdate 更新前状态===============》'); //这里指的是页面渲染新数据之前
console.log("%c%s", "color:green","el : " + this.$el);
console.log(this.$el);
console.log("%c%s", "color:green","data : " + this.$data);
console.log("%c%s", "color:green","message: " + this.message);
alert("更新前状态2");
},
updated: function () {
console.group('updated 更新完成状态===============》');
console.log("%c%s", "color:green","el : " + this.$el);
console.log(this.$el);
console.log("%c%s", "color:green","data : " + this.$data);
console.log("%c%s", "color:green","message: " + this.message);
},
beforeDestroy: function () {
console.group('beforeDestroy 销毁前状态===============》');
console.log("%c%s", "color:red","el : " + this.$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 销毁完成状态===============》');
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>
