vue实现原理this.$message实例详解

import Vue from 'vue';
import Confirm from './index.vue'; // 引入组件
let newInstance;
const ConfirmInstance = Vue.extend(Confirm); // 创建构造函数
const initInstance = () => { // 执行方法后完成挂载
	newInstance = new ConfirmInstance(); // 实例化
	document.body.appendChild(newInstance.$mount().$el);
// 实例化后手动挂载，得到$el真实Dom，将其添加到body最后
}
export default options => {
//导出一个方法，接受配置参数
if (!newInstance) {
	initInstance(); // 挂载
}
Object.assign(newInstance, options);
// 实例化后newInstance就是一个对象了，所以data内的数据会
// 挂载到this下，传入一个对象与之合并
return newInstance.show(vm => { // 显示弹窗
	newInstance = null; // 将实例对象清空
})
}

<template>
  <!-- 二次确认弹窗 -->
  <el-dialog width="440px" class="delete-confirm" :visible.sync="confirmDialigShow" :show-close="false"
    :close-on-click-modal="false">
    <div class="top">
      <img class="danger" :src="require('./danger.png')">
      <div class="title">{{ title }}</div>
    </div>
    <div class="bottom">{{ content }}</div>
    <span slot="footer" class="dialog-footer">
      <el-button v-if="showCancelButton" size="small" @click="cancel">{{ cancelButtonText || '取消' }}</el-button>
      <el-button size="small" type="primary" @click="confirm">{{ confirmButtonText || '确定' }}</el-button>
    </span>
  </el-dialog>
</template>
<script>
export default {
  data() {
    return {
      title: '提示',
      content: '该数据删除将无法恢复，是否确认删除？',
      confirmButtonText: '确定',
      cancelButtonText: '取消',
      showCancelButton: true,
      confirmDialigShow: true
    }
  },
  methods: {
    show(cb) {
      this.showFlag = true
      typeof cb === "function" && cb.call(this, this)
      return new Promise((resolve, reject) => {
        this.reject = reject
        this.resolve = resolve
      })
    },
    cancel() {
      this.reject("cancel")
      this.hide()
    },
    confirm() {
      this.resolve("confirm")
      this.hide()
    },
    hide() {
      this.showFlag = false
      document.body.removeChild(this.$el)
      this.$destroy()
    }
  }
}
</script>
<style lang='scss' scoped>
.delete-confirm {
  // width: 440px;
  box-shadow: 0px 4px 12px 0px rgba(0, 0, 0, 0.1);
  border-radius: 4px;
  .top {
    display: flex;
    align-items: center;
    margin-bottom: 12px;
    .danger {
      width: 30px;
      height: 24px;
      margin-right: 12px;
    }
    .title {
      font-weight: 500;
      font-size: 16px;
      color: rgba(0, 0, 0, 0.85);
      line-height: 24px;
    }
  }
  .bottom {
    font-size: 14px;
    font-weight: 400;
    color: #324457;
    line-height: 22px;
    margin-top: 20px;
  }
  ::v-deep .el-dialog__header {
    display: none;
  }
  ::v-deep {
    .el-dialog {
      margin-top: 20vh !important;
    }
    .el-dialog__body {
      padding: 24px;
    }
    .el-dialog__footer {
      border: none;
      line-height: 0;
      padding: 8px 24px 24px 0 !important;
    }
  }
}
</style>

import esConfirm from '@/components/esConfirm/index.js'
Vue.prototype.$esConfirm = esConfirm

this.$esConfirm({
title: '是否删除？'
}).then(res => {
console.log(res)
}).catch(error => {
console.log(error)
})

                    this.$message({
                        message:'保存成功了，我是message',
                        type: 'success'
                    })

axios.post("http://localhost:3312/user/save",this.form).then((resp)=>{
                let data = resp.data
                if(data.success){
                   ......
                    this.$message({
                        message:'保存成功了，我是message',
                        type: 'success'
                    })
                }
         })