vue 生命周期和钩子函数

作者: 程序萌 | 来源:发表于2018-10-12 18:00 被阅读0次

Vue的生命周期与钩子函数
vue 获取节点获取事件
详细的分析 Vue生命周期
深入浅出Vue生命周期钩子函数
学习链接
什么是生命周期钩子函数？
Vue-计算属性和监听属性
Vue生命周期
vue生命周期分析
😄--前端面试整理--VueJs

官方生命周期图：

image.png

列表图

image.png

总结

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

实际开发中如何使用

beforecreate : 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
beforeDestroy：你确认删除XX吗？ destroyed ：当前组件已被删除，清空相关内容

贴下代码：

在chrome中打开 console即可查看

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>vue-lifecycle</title>
   <script src="https://unpkg.com/vue/dist/vue.js"></script>
</head>
<body>

  <hr>
  <div id="container">
      <button @click="changeMsg()">点击刷新</button>
      <button @click="destroy()">destroy</button>
      <h4>{{'页面加载状态信息监听 :'+msg}}</h4>
  </div>

  <script type="text/javascript">
    var vm = new Vue({
      // el:'#container',
      data:{
        msg:'初始加载',
        i: 0
      },
      beforeCreate(){
        console.group("%c%s","color:red",'beforeCreate--实例创建前状态')
        console.log("%c%s","color:blue","el  :"+this.$el) //undefined
        console.log("%c%s","color:blue","data  :"+this.$data) //undefined
        console.log("%c%s","color:blue","msg  :"+this.msg) //undefined
      },
      created() {
        console.group("%c%s","color:red",'created--实例创建完成状态')
        console.log("%c%s","color:blue","el  :"+this.$el) //undefined
        console.log("%c%s","color:blue","data  :"+this.$data) //已被初始化 
        console.log("%c%s","color:blue","msg  :"+this.msg) //已被初始化 
      },
      beforeMount() {
        console.group("%c%s","color:red",'beforeMount--挂载之前的状态')
        console.log("%c%s","color:blue","el  :"+this.$el) //已被初始化 
        console.log(this.$el);
        console.log("%c%s","color:blue","data  :"+this.$data)
        console.log("%c%s","color:blue","msg  :"+this.msg)
        console.log("%s%o","document.getElementById('container'): ",document.getElementById('container'))
      },
      mounted() {
        console.group("%c%s","color:red",'mounted--已经挂载的状态')
        console.log("%c%s","color:blue","el  :"+this.$el)
        console.log(this.$el);
        console.log("%c%s","color:blue","data  :"+this.$data)
        console.log("%c%s","color:blue","msg  :"+this.msg)
        console.log("%s%o","document.getElementById('container'): ",document.getElementById('container'))
      },
      beforeUpdate(){
        console.group("%c%s","color:red",'beforeUpdate--数据更新前的状态')
        if(this.$el.innerHTML){
          console.log("%c%s","color:blue","el  :"+this.$el.innerHTML)
        }
        console.log(this.$el);
        console.log("%c%s","color:blue","data  :"+this.$data)
        console.log("%c%s","color:blue","msg  :"+this.msg)
        if(document.getElementById('container')!=null){
          console.log("%c%s","color:green","真实的 DOM 结构:"+document.getElementById('container').innerHTML)
        }
      },
      updated() {
        console.group("%c%s","color:red",'updated--数据更新完成时状态')
        console.log("%c%s","color:blue","el  :"+this.$el.innerHTML)
        console.log(this.$el);
        console.log("%c%s","color:blue","data  :"+this.$data)
        console.log("%c%s","color:blue","msg  :"+this.msg)
        if(document.getElementById('container')!=null){
          console.log("%c%s","color:green","真实的 DOM 结构:"+document.getElementById('container').innerHTML)
        }
      },
      activated() {
        console.group("%c%s","color:red",'activated-- keep-alive 组件激活时调用')
        console.log("%c%s","color:blue","el  :"+this.$el)
        console.log(this.$el);
        console.log("%c%s","color:blue","data  :"+this.$data)
        console.log("%c%s","color:blue","msg  :"+this.msg)
      },
      deactivated(){
        console.group("%c%s","color:red",'deactivated-- keep-alive 停用时调用')
        console.log("%c%s","color:blue","el  :"+this.$el)
        console.log(this.$el);
        console.log("%c%s","color:blue","data  :"+this.$data)
        console.log("%c%s","color:blue","msg  :"+this.msg)
      },
      beforeDestroy() {
        console.group("%c%s","color:red",'beforeDestroy-- vue实例销毁前的状态')
        console.log("%c%s","color:blue","el  :"+this.$el)
        console.log(this.$el);
        console.log("%c%s","color:blue","data  :"+this.$data)
        console.log("%c%s","color:blue","msg  :"+this.msg)
      },
      destroyed() {
        console.group("%c%s","color:red",'destroyed-- vue实例销毁完成时调用')
        console.log("%c%s","color:blue","el  :"+this.$el)
        console.log(this.$el);
        console.log("%c%s","color:blue","data  :"+this.$data)
        console.log("%c%s","color:blue","msg  :"+this.msg)
      },
      methods: {
        changeMsg() {
          this.msg = '刷新了' + this.i++ + '次';
        },
        destroy() {
          this.$destroy()
        }
      },
    })
    vm.$mount('#container')
  </script>
</body>
</html>