Vue生命周期对vue对象的影响

来源：互联网发布：淘宝关键词竞争力公式编辑：程序博客网时间：2024/05/20 02:53

在查找资料的时候看到了vue的生命周期图，然后拿下来一下，相关链接：
https://segmentfault.com/a/1190000008010666

这里写图片描述

链接里面解释了不同时期vue内部的数据情况，但是没有解释vue对象的生成情况，对于链接中的代码：

<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     : " + app); //undefined            console.log("%c%s", "color:red", "el     : " + this); //已被初始化            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     : " + app); //undefined            console.log("%c%s", "color:red", "el     : " + this); //已被初始化            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     : " + app); //undefined            console.log("%c%s", "color:red", "el     : " + this); //已被初始化            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.$data); //已被初始化              console.log("%c%s", "color:red", "message: " + this.message); //已被初始化          },        mounted: function () {            console.group('mounted 挂载结束状态===============》');            console.log("%c%s", "color:red", "el     : " + app); //undefined            console.log("%c%s", "color:red", "el     : " + this); //已被初始化            console.log("%c%s", "color:red", "el     : " + this.$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     : " + app); //已被初始化            console.log("%c%s", "color:red", "el     : " + this); //已被初始化            console.log("%c%s", "color:red", "el     : " + this.$el);            console.log(this.$el);            console.log("%c%s", "color:red", "data   : " + this.$data);            console.log("%c%s", "color:red", "message: " + this.message);        },        updated: function () {            console.group('updated 更新完成状态===============》');            console.log("%c%s", "color:red", "el     : " + app); //已被初始化            console.log("%c%s", "color:red", "el     : " + this); //已被初始化            console.log("%c%s", "color:red", "el     : " + this.$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     : " + app); //已被初始化            console.log("%c%s", "color:red", "el     : " + this); //已被初始化            console.log("%c%s", "color:red", "el     : " + this.$el);            console.log(this.$el);            console.log("%c%s", "color:red", "data   : " + this.$data);            console.log("%c%s", "color:red", "message: " + this.message);        },        destroyed: function () {            console.group('destroyed 销毁完成状态===============》');            console.log("%c%s", "color:red", "el     : " + app); //已被初始化            console.log("%c%s", "color:red", "el     : " + this); //已被初始化            console.log("%c%s", "color:red", "el     : " + this.$el);            console.log(this.$el);            console.log("%c%s", "color:red", "data   : " + this.$data);            console.log("%c%s", "color:red", "message: " + this.message)        }    })</script>

其中的名字为app的vue对象，是在mounted状态之后才可用的，也就是说如果在beforeCreate、created、beforeMount、mounted这几个状态的时候使用app来访问数据或者调用方法，都是会报错的，因为app为空，但如何使用数据呢，这个时候就要用this了，this里面在created之后是有data值的，在这里也能看出来this和app还是有区别的

阅读全文

0 0