1、起步

<template>
   <div>
     <p><button @click="add">{{count}}</button></p>
   </div>
</template>
<script setup>
import { onMounted, onUpdated, reactive, toRefs} from 'vue'
const state = reactive({
  count:1,
  add(){
    state.count++
  }
})
const {count,add} = toRefs(state);
onMounted(()=>{
  setTimeout(()=>{
    state.count = 4
  },1000)
})
onUpdated(()=>{
  console.log(state.count)
})
</script>