vue3 watchEffect

<el-button type="primary" plain round @click="stop">stop</el-button>

const stop = watchEffect((onInvalidate) => {
  console.log(massage.value);
  onInvalidate(()=>{
  console.log('2');  //这个回先执行，log 2,然后log massage.value

}),{

flush:'post'，

 onTrack?: (event: DebuggerEvent) => void  调试bug用
  onTrigger?: (event: DebuggerEvent) => void

} }) flush:'post' //添加flush:'post' 组件更新后执行对应方法，sync 强制效果始终同步触发   pre组件更新前执行