index.vue

<template>
  <div class="box">
    <div :class="['box-main ', { active: isShow }]">{{ info }}==={{shijain}}</div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      info: "",
      shijain:'',
      isShow: false,
    };
  },
  mounted() {
    setTimeout(() => {
      this.isShow = true;
    }, 2000);
  },
  methods: {},
};
</script>

<style scoped>
.box {
  width: 100%;
  height: 100%;
  position: relative;
}
.box-main {
  width: 150px;
  min-height: 50px;
  background: #ccc;
  text-align: center;
  line-height: 50px;
  border-radius: 10px;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}
.active {
  transition: all 1s;
  opacity: 0;
}
</style>

index.js

import Vue from 'vue'
import Message from './index.vue'

let MessageConstructor = Vue.extend(Message)
let instance
const MessageTip = function (options = {}) {
    instance = new MessageConstructor({
        data: options
    })
    document.body.appendChild(instance.$mount().$el) //this.$el拿到组件实际上的dom，把他挂载到body上
    setTimeout(() => {
        document.body.removeChild(instance.$mount().$el)
    }, 3000);  //3秒之后自动移除dom组件

}

export default MessageTip

在main.js 全局挂载

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

页面使用

<template>
  <div id="app">
    <button @click="showdialog">显示弹框1</button>
    <button @click="showdialog2">显示弹框2</button>
    <button @click="showdialog3">显示弹框3</button>
  </div>
</template>
<script>
export default {
  methods:{
    showdialog(){
      this.$MessageTip({info:'哈哈',shijain:new Date()})
    },
    showdialog2(){
      this.$MessageTip({info:'哈哈222'})
    },
    showdialog3(){
      this.$MessageTip({info:'哈哈333'})
    }
  }
}
<script>

参考：
https://www.cnblogs.com/zienlove/p/16186758.html
https://blog.csdn.net/HockJerry/article/details/115750572