let obj = {a:1,b:2}
let obj2 = {...obj1}
obj.b = 3
console.log(obj)
//{a:1,b:2}

解读“let obj2 = {...obj1}”：新建一个空对象{}，把obj的键值解构到空对象{}，把这个对象赋值给obj2。这个过程新建了对象，指针自然不会指向obj