this.$Confirm({
 title:'自定义标题'
}).then(res=>{
  console.log(res)
})

<template>
  <div class="wrap">
    <div class="main">
      <div class="content">
        {{title}}
      </div>
      <div class="btn-grounp">
        <div class="btn cancel" @click="cancel">{{cancelText}}</div>
        <div class="btn confirm" @click="confirm">{{confirmText}}</div>
      </div>
    </div>
  </div>
</template>

<script>
export default {
  name:'',
  data () {
    return {
      title:'这是一个弹窗',
      confirmText:'确定',
      cancelText:'取消'
    };
  },
  methods: {
    show(cb){
      typeof cb === 'function' && cb.call(this,this)
      return new Promise(resolve=>{
        this.resolve = resolve
      })
    },
    confirm(){
      this.resolve('confirm')
      this.hide()
    },
    cancel(){
      this.resolve('cancel')
      this.hide()
    },
    hide(){
      document.body.removeChild(this.$el)
      this.$destroy()
    }
  },
}

</script>

<style scoped>
.wrap{
  position: fixed;
  top: 0;
  bottom:0;
  left:0;
  right:0;
  display:flex;
  justify-content: center;
  align-items: center;
  background: rgba(0,0,0,.3);
}
.main{
  width: 30%;
  padding: 10px;
  background: #fff;
  box-shadow: 0 0 10px 1px #ddd;
  border-radius: 5px;
}
.content{
  color:#424242;
  font-size: 20px;
}
.btn-grounp{
  margin-top: 15px;
  display:flex;
  justify-content: flex-end;
}
.btn{
  margin-left: 15px;
  padding: 5px 20px;
  border-radius: 5px;
  font-size: 16px;
  color:#fff;
}
.confirm{
  background: lightblue;
}
.cancel{
  background: lightcoral;
}
</style>

import Vue from 'vue'
import comfirm from './index.vue'
let newInstance = null
//将vue组件变为构造函数
let ConfirmConstructor = Vue.extend(comfirm)
let init = (options)=>{
  //实例化组件
  newInstance = new ConfirmConstructor()
  //合并配置选项
  Object.assign(newInstance,options)
  //加载dom
  document.body.appendChild(newInstance.$el)
}
let caller = (options)=>{
  //options 为调用组件方法时传入的配置选项
  if(!newInstance){
    init(options)
  }
  return newInstance.show(vm =>{newInstance = null})
}
export default {
  install(vue){
    vue.prototype.$Confirm = caller
  }
}

import Confirm from './components/confirm'
Vue.use(Confirm)