生命周期
我们执行以下代码：
<!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 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)
},
created: function() {
console.group('created 创建完毕状态===============》');
console.log("%c%s", "color:red", "el : " + this.$el); //undefined
console.log("%c%s", "color:red", "data : " + this.$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 挂载前状态===============》');
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.$data); //已被初始化
console.log("%c%s", "color:red", "message: " + this.message); //已被初始化
},
mounted: function() {
console.group('mounted 挂载结束状态===============》');
console.log("%c%s", "color:red", "el : " + this.$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.$data);
console.log("%c%s", "color:red", "message: " + this.message);
},
updated: function() {
console.group('updated 更新完成状态===============》');
console.log("%c%s", "color:red", "el : " + this.$el);
console.log(this.$el);
console.log("%c%s", "color:red", "data : " + this.$data);
console.log("%c%s", "color:red", "message: " + this.message);
},
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>
可以看出，
beforecreated：el 和 data 并未初始化
created:完成了 data 数据的初始化，el没有
beforeMount：完成了 el 和 data 初始化
mounted ：完成挂载
如何用
beforecreate : 举个栗子：可以在这加个loading事件
created ：在这结束loading，还做一些初始化，实现函数自执行
mounted ： 在这发起后端请求，拿回数据，配合路由钩子做一些事情
beforeDestory： 你确认删除XX吗？ destoryed ：当前组件已被删除，清空相关内容