Question

我想＆＃34;延伸＆＃34;来自现有类的新类，包括它的方法和参数构造。

System = function(name, hp){
  this.name = name;
  this.hp = [];
  this.setHP = function(hp){
     this.hp[0] = hp;
     this.hp[1] = hp;
  }
  this.setHP(hp);
}

Weapon = function(name, hp){
   System.call(this);
}

Weapon.prototype = new System(name, hp);
Weapon.prototype.constructor = Weapon;


var gun = new Weapon("Gun", 10);    // undefined name, hp
var hangar = new System("Hangar", 10);    // works

所以，就我而言，有人显然是错的。有人可以告诉我吗？

Answer 1

您需要在调用中传递参数：

System.call(this, name, hp);

另外，请注意Weapon.prototype = new System(name, hp);可能会产生副作用，最好使用以下方法：

Weapon.prototype = Object.create(System.prototype);

如果您需要支持古老的浏览器，可以找到Object.create的填充。

Answer 2

System = function(name, hp){
  this.name = name;
  this.hp = [];
  this.setHP = function(hp){
     this.hp[0] = hp;
     this.hp[1] = hp;
  }
  this.setHP(hp);
}
Weapon = function(name, hp){
    System.apply(this, arguments);
}

console.log(new Weapon("Gun", 10));
console.log(new System("Hangar", 10));

结果：

Weapon {name: "Gun", hp: Array[2], setHP: function}
System {name: "Hangar", hp: Array[2], setHP: function}

带参数的Javascript“class”扩展名？

2 个答案: