vue4+提供了useStore，引入useStore，其他写法就可以和之前的写法类似，具体如下：
<template>
<div>{{ $store.state.count }}</div>
<button @click="myCommit ">点击</button>
</template>
script:
import { useStore } from 'vuex';
setup(){
const store = useStore();
// 取值
//store.state.count
//commit提交
const myCommit = () =>{
store.commit("commitValue")
}
return { myCommit }
}