coffeescript扩展类的构造函数

Question

class RedGuy 
     constructor : (@name) -> 
      @nameElem = $ @name 
      @nameElem.css color : red 

class WideRedGuy extends RedGuy 
     constructor : -> 
      @nameElem.css width : 900 

jeff = new WideRedGuy '#jeff' 

我想#jeff是红色和宽，但我总是得到this.name is undefined。我如何扩展构造函数（追加？），以便我可以访问原始对象的属性？

Answer 1

您需要明确地调用super才能使其工作。调用super在WideRedGuy将调用RedGuy的构造函数，之后@nameElem将被正确定义。有关更深入的解释，您应该就此问题咨询coffeescript's documentation。

class RedGuy 
     constructor : (@name) -> 
      @nameElem = $ @name 
      @nameElem.css color : red 

class WideRedGuy extends RedGuy 
     constructor : -> 
      ## This line should fix it 
      super # This is a lot like calling `RedGuy.apply this, arguments` 
      @nameElem.css width : 900 

jeff = new WideRedGuy '#jeff'