编写一个“扩展”函数来简化基于 JS 的继承 [重复]

Question

我是 Java 脚本世界的新手，我们怎么能用 Java 脚本编写代码。

 function Car() {
     this.type = "Car";
   };

function Ferrari() {
     this.name = "Ferrari";
   };

Ferrari.extends(Car);
   var f = new Ferrari();
   f.name // Ferrari
   f.type // Car

当我关注eloquentjavascript book 时，没有一个答案可以帮助我

Answer 1

Javascipt 是一种采用prototypical 方法的混合语言。在 js 上下文中“扩展”就是通过原型继承。一些现代浏览器支持 Object.create() ，它在内部迭代每个原型属性并复制。

这个sn-p来自MDN：

Examples
Example: Classical inheritance with Object.create()

Below is an example of how to use Object.create() to achieve classical inheritance. This is for single inheritance, which is all that JavaScript supports.

// Shape - superclass
function Shape() {
  this.x = 0;
  this.y = 0;
}

// superclass method
Shape.prototype.move = function(x, y) {
  this.x += x;
  this.y += y;
  console.info('Shape moved.');
};

// Rectangle - subclass
function Rectangle() {
  Shape.call(this); // call super constructor.
}

// subclass extends superclass
Rectangle.prototype = Object.create(Shape.prototype);
Rectangle.prototype.constructor = Rectangle;

var rect = new Rectangle();

console.log('Is rect an instance of Rectangle? ' + (rect instanceof Rectangle)); // true
console.log('Is rect an instance of Shape? ' + (rect instanceof Shape)); // true
rect.move(1, 1); // Outputs, 'Shape moved.'

希望这会有所帮助。