<template>
<transition name='fade'>
 <div class="alert" v-if="showAlert">
  <div class="wrap">
   <div class="head">{{title}}</div>
   <div class="body">
    <slot>
     <p>{{message}}</p>
    </slot>
   </div>
   <div class="foot">
    <div v-if="type === 'confirm'">
     <button class="btn-base" @click="sure">确定</button>
     <button class="btn-gray" @click="cancel">取消</button>
    </div>
    <div v-else-if="type === 'inform'">
     <button class="btn-base" @click="cancel">知道了</button>
    </div>
   </div>
  </div>
 </div>
</transition>
</template>
<script>
export default {
 name: 'alert',
 data() {
  return {
   showAlert: false,
  };
 },
 props: {
  title: {
   type: String,
   default: '提示',
  },
  message: {
   type: String,
  },
  type: { // 可以有confirm, 和inform两个类型
   type: String,
   default: 'confirm',
   validator(value) {
    return value === 'confirm' || value === 'inform';
   },
  },
  sureBtn: {
   type: Function,
  },
  cancelBtn: {
   type: Function,
  },
  context: {
   type: Object,
  },
 },
 methods: {
  cancel() {
   if (this.cancelBtn) {
    this.cancelBtn.apply(this.context);
   }
   this.close();
  },
  sure() {
   if (this.sureBtn) {
    this.sureBtn.apply(this.context);
   }
   this.close();
  },
  show() {
   this.showAlert = true;
  },
  close() {
   this.showAlert = false;
  },
 },
};
</script>
<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped lang='scss'>
.alert {
 position: fixed;
 top: 0;
 left: 0;
 right: 0;
 bottom: 0;
 background: rgba(0,0,0, 0.8);
 z-index: 1000;
 transition: all .3s ease-in-out;
}
.wrap {
 position: absolute;
 z-index: 1002;
 min-width: 400px;
 background: #fff;
 left: 50%;
 top: 50%;
 transform: translate(-50%, -50%);
 border-radius: 4px;
}
.head {
 height: 40px;
 line-height: 40px;
 border-bottom: 1px solid #dedede;
 padding-left: 10px;
 color: #333;
}
.body {
 padding: 40px 20px;
 text-align: center;
}
.foot {
 height: 50px;
 text-align: center;
 button {
  margin-right: 20px;
  &:last-child {
   margin-right: 0;
  }
 }
}
</style>

<!--template-->
<button @click="showAlert">点我</button>
<alert ref="alert">我是一个确认框</alert>
<!--javascript-->
...
methods: {
  showAlert() {
    this.$refs.alert.show();
  }
}
...

import Vue from 'vue';
import alert from './alert';
const AlertConstructor = Vue.extend(alert);
const div = document.createElement('div');
AlertConstructor.show = (options) => {
 document.body.appendChild(div);
 options.type = 'inform';
 const propsData = Object.assign({}, options);
 const alertInstance = new AlertConstructor({
  propsData,
 }).$mount(div);
 alertInstance.show();
};
AlertConstructor.confirm = (options) => {
 document.body.appendChild(div);
 options.type = 'confirm';
 const propsData = Object.assign({}, options);
 const alertInstance = new AlertConstructor({
  propsData,
 }).$mount(div);
 alertInstance.show();
};
export default AlertConstructor;