javascript - 如何使 “toString”方法私有(private)？

对于“武器”，如何实现方法“toString”，Object.keys()无法使用该方法。

function Weapon(name,damage) {
    this.name = name;
    this.damage = damage;
    this.toString = function () {
        return this.name + this.damage + " damage";
    }
}
var bow = new Weapon(' Golden bow, ',20);
var sword = new Weapon(' Magic sword, ', 40);
console.log(bow.toString());
console.log(sword.toString());
Object.defineProperty(Weapon, "toString", {enumerable: false});

最佳答案

从MDN关于Object.keys():



因此，要么将属性设置为不可枚举的:

function Weapon(name,damage) {
    this.name = name;
    this.damage = damage;
    Object.defineProperty(this, 'toString', {
      value: function () {
        return this.name + this.damage + " damage";
      },
      // enumerable: false, // is implicitly set
    });
}

或通过在原型(prototype)上对其进行定义，使其成为而不是“拥有”属性:

function Weapon(name,damage) {
    this.name = name;
    this.damage = damage;
}

Weapon.prototype.toString = function () {
  return this.name + this.damage + " damage";
};

如果您使用class语法，则将“免费”获得两个:

class Weapon {
  constructor(name,damage) {
    this.name = name;
    this.damage = damage;
  }

  toString()
    return this.name + this.damage + " damage";
  }
}

toString将在原型(prototype)上定义，并且无法枚举。