在Javascript中扩展对象 [英] Extending an Object in Javascript

问题描述

我现在正在从Java转换为Javascript，并且我很难弄清楚如何按照我希望的方式扩展对象。

我已经看到互联网上的几个人使用了一种称为扩展对象的方法。代码如下所示：

  var Person = {
 name：'Blank'，
 age ：22 
} 
 
 var Robot = Person.extend（{
 name：'Robo'，
 age：4 
）} 
 
 var robot = new Robot（）; 
 alert（robot.name）; //应该返回'Robo'
  

有人知道如何使这项工作成功吗？
我听说你需要编写

  Object.prototype.extend = function（...）; 
  

但我不知道如何让这个系统工作。如果这是不可能的，请向我展示另一个扩展对象的替代方案。

在使用代码之前，请检查user2491400中有关简单分配给原型的副作用的评论。

原始答案：

您想从Person的原型对象'继承'：

  var Person = function（name）{
 this.name = name; 
 this.type ='human'; 
 
 
 Person.prototype.info = function（）{
 console.log（Name：，this.name，Type：，this.type）; 
} 
 
 var Robot = function（name）{
 Person.apply（this，arguments）
 this.name = name; 
 this.type ='robot'; 
} 
 
 Robot.prototype = Person.prototype; //将原型设置为Person的
 Robot.prototype.constructor = Robot; //将构造函数设置回Robot 
 $ b person = new Person（Bob）; 
 robot = new Robot（Boutros）; 
 
 person.info（）; 
 //名称：Bob类型：人类
 
 robot.info（）; 
 //名称：Boutros类型：机器人
  

I am currently transforming from Java to Javascript, and it's a bit hard for me to figure out how to extend objects the way I want it to do.

I've seen several people on the internet use a method called extend on object. The code will look like this:

var Person = {
   name : 'Blank',
   age  : 22
}

var Robot = Person.extend({
   name : 'Robo',
   age  : 4
)}

var robot = new Robot();
alert(robot.name); //Should return 'Robo'

Does anyone know how to make this work? I've heard that you need to write

Object.prototype.extend = function(...);

But I don't know how to make this system work. If it is not possible, please show me another alternative that extends an object.

解决方案

Edit:
Before using the code, please check the comments from user2491400 that reports about the side effects of simply assigning to prototype.

Original answer:

You want to 'inherit' from Person's prototype object:

var Person = function(name){
  this.name = name;
  this.type = 'human';
}

Person.prototype.info = function(){
  console.log("Name:", this.name, "Type:", this.type);
}

var Robot = function(name){
  Person.apply(this,arguments)
  this.name = name;
  this.type = 'robot';
}

Robot.prototype = Person.prototype;        // Set prototype to Person's
Robot.prototype.constructor = Robot;   // Set constructor back to Robot

person = new Person("Bob");
robot = new Robot("Boutros");

person.info();
// Name: Bob Type: human

robot.info();
// Name: Boutros Type: robot

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