vue3监听响应式对象

 let book = reactive({
     name: "js编程",
     price: 50,
 });
 const changeBookName = () => {
 	book.name = "c#"; 
 };
 watch(()=>book.name,()=>{//通过一个函数返回要监听的属性
 	console.log('书名改变了')
 })