javascript - 未捕获的语法错误 : Setter must have exactly one formal parameter

Question

我试图理解 JS 上的 getter 和 setter，但我似乎无法通过此错误。任何人都可以提供关于为什么我会收到此错误的任何见解吗？

var book = {
    year: 2004,
    edition:1,
    get newYear(){
        return "Hello, it's " + this.year;
    },
    set newYear(y, e){
        this.year = y;
        this.edition = e;
    }
};

Uncaught SyntaxError: Setter must have exactly one formal parameter

Answer 1

当您分配 setter 代表的值时调用 setter 函数:

var obj = {
  set a(newVal) { console.log("hello"); }
}
obj.a = 1; // will console log "hello"

如您所见，setter 接受多个参数是没有意义的，但它使您可以在设置值之前自由地操作该值:

var person = {
  surname: "John",
  lastname: "Doe",
  get fullname() {
    return this.surname + " " + this.lastname;
  },
  set fullname(fullname) {
    fullname = fullname.split(' ');
    this.surname = fullname[0];
    this.lastname = fullname[1];
  }
};

console.log(person.fullname); // "John Doe"
person.fullname = "Jane Roe";
console.log(person.surname); // "Jane"
console.log(person.lastname); // "Roe"