javascript - 是否可以通过指针使对象为 null 或 undefined ？

Question

let person = {name: "Annah", age: 18};
let pointer = person;
pointer = undefined;

人不会变成undefined，只是指针？

Answer 1

您可以使用包装对象模拟该行为:

const reference = value => ({ 
  value,
  free() { this.value = undefined },
});

const val = ref => ref.value;

let person = reference({name: "Annah", age: 18});
let pointer = person;

console.log(val(person));

pointer.free();

console.log(val(person));

因此您无法再访问 person.name，您必须使用 val(person).name 取消引用它。

---

理论上，您可以创建两个引用同一事物的变量:

with({ 
 person: undefined,
 get pointer() { return this.person; },
 set pointer(value) { this.person = value },
}) {
  person = { some: "test" };
  console.log(pointer);
  pointer = undefined;
  console.log(person);
}

但是请不要那样做(除非是为了好玩)。