一起来做一下Vue全局提示组件

message.info('This is a normal message')

<!-- Message.vue -->
<template>
  <div>{{ content }}</div>
</template>

<script>
export default {
  name: 'Message',
  props: {
    content: {
      type: String,
      default: ''
    }
  }
}
</script>

// index.js
import { render, createVNode } from 'vue'
import Message from './Message.vue'

export default function message (content) {
  const div = document.createElement('div')
  const vm = createVNode(Message, {
    content
  })
  render(vm, div)
  document.body.appendChild(div)
}

<!-- app.vue -->
<template>
</template>
<script>
import message from './components/message'
export default{
  setup() {
    message('消息组件1')
    message('消息组件2')
  }
}
</script>

const div = document.createElement('div')
const vm = createVNode(Message, {
  content
})
render(vm, div)
document.body.appendChild(div)

<!-- Message.vue -->
<script>
import { ref, unref } from 'vue'
export default {
  name: 'Message',
  setup (props, { expose }) {
    // 消息列表
    const messages = ref([])
    
    let id = 0
    // 生成id
    const uuid = () => `message_${id++}`
    
    // 添加消息对象
    const add = (message) => {
      const id = uuid()
      const _message = {
        ...message,
        id
      }
      unref(messages).push(_message)
      const { duration = 3 } =  message
      // 设置定时器
      const timer = setTimeout(() => {
        clearTimeout(timer)
        remove(id)
      }, duration * 1000)
    }
    
    // 根据 id 删除消息对象
    const remove = (id) => {
      messages.value = unref(messages).filter(message => message.id !== id)
    }
    
    // 暴露出add 和 remove
    expose({
      add
    })
    
    return {
      messages
    }
  }
}
</script>

<!-- Message.vue -->
<template>
  <transition-group
    class="message"
    tag="div"
  >
    <div
      class="message-content"
      v-for="message in messages"
      :key="message.id"
    >
      {{ message.content }}
    </div>
  </transition-group>
</template>

<!-- Message.vue -->
<style scoped>
.message {
  position: fixed;
  z-index: 999;
  top: 10px;
  left: 50%;
  transform: translateX(-50%);
}

.message-content {
  padding: 8px 16px;
  border-radius: 3px;
  box-shadow: 0 1px 6px rgba(0, 0, 0, .2);
  background: #fff;
  margin-bottom: 20px;
}

.v-enter-active,
.-leave-active {
  transition: all 200ms ease-in;
}
.v-enter-from,
.v-leave-to {
  opacity: 0;
  transform: translateY(-30px);
}
</style>

// index.js
import { render, createVNode } from 'vue'
import Message from './Message.vue'

let vm
// 使用单例模式，不再重新插入body
function getMessageInstance () {
  if (vm) return
  const div = document.createElement('div')
  vm = createVNode(Message)
  render(vm, div)
  document.body.appendChild(div)
}

export default function message (content = '', duration) {
  getMessageInstance()
  vm.component.exposed.add({
    content,
    duration
  })
}

<!-- app.vue -->
<template>
  <button @click="onClick">测试</button>
</template>
<script>
import message from './components/message'
export default{
  setup() {
    message('消息组件1', 4)
    message('消息组件2', 2)
    let index = 3
    const onClick = () => {
      message(`消息组件${index++}`)
    }
    return {
      onClick
    }
  }
}
</script>