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  • vue生命周期和钩子函数的理解

    vue生命周期简介

                 

    生命周期探究

    对于执行顺序和什么时候执行,看上面两个图基本有个了解了。下面我们将结合代码去看看钩子函数的执行。

      

    <!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>

    create 和 mounted 相关

    chrome浏览器里打开,F12console就能发现

    update 相关

    这里我们在 chrome console里执行以下命令

    下面就能看到data里的值被修改后,将会触发update的操作

    destroy 相关

    有关于销毁,暂时还不是很清楚。我们在console里执行下命令对 vue实例进行销毁。销毁完成后,我们再重新改变message的值,vue不再对此动作进行响应了。但是原先生成的dom元素还存在,可以这么理解,执行了destroy操作,后续就不再受vue控制了。

    生命周期总结

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  • 原文地址:https://www.cnblogs.com/zxyzm/p/10672878.html
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