在嵌套函数中引用类对象时出现问题 [英] Trouble referencing class object inside a nested function

问题描述

我想在coffeescript中创建一个类，我几乎在那里。我的问题是，我想为类的整个范围创建一对夫妇的变量，但我不知道如何到嵌套函数内。 @等效于this。，但是我想能够从类中的任何地方获得这些构造函数的属性。

示例：

  class CoffeeScriptClass 
 constructor：（@foo） - > 
 
 _sampleFunction： - > 
 $ .each BigArray，（index，NestedArray） - > 
 $ .each NestedArray，（index，widget） - > 
 
 ##我想@foo引用构造函数值
 
 widget = @foo 
 
 return 
 return 
 return 
  

这是否有意义？我真的想保持我的OO Javascript整洁和有组织，但我有一个困难的时间与咖啡的范围部分。我很高兴地欢迎任何重构/建议在我的课余下。

解决方案

您需要限定内部函数的范围：

  class CoffeeScriptClass 
 constructor：（@foo） - > 
 
 _sampleFunction： - > 
 $ .each BigArray，（index，NestedArray）=> //保持父作用域
 $ .each NestedArray，（index，widget）=> //保持父作用域
 
 ##我想要@foo引用构造函数值
 
 widget = @foo 
 
 return 
 return 
 return 
  
 
 
 
 
 
 
编译的JS显示为什么这样工作：
  var CoffeeScriptClass; 
 
 CoffeeScriptClass =（function（）{
 
 function CoffeeScriptClass（foo）{
 this.foo = foo; 
} 
 
 CoffeeScriptClass.prototype._sampleFunction = function（）{
 
 var _this = this; //维护对类的引用
 
 $ .each（BigArray，function ，NestedArray）{
 $ .each（NestedArray，function（index，widget）{
 widget = _this.foo; 
}）; 
}）; 
} ; 
 
 return CoffeeScriptClass; 
 
}）（）; 
  
 
I'm trying to create a class in coffeescript and I'm almost there. My problem is, I'd like to create a couple of variables for the entire scope of the class, however I don't know how to get to them inside nested functions. @ is equivalent to "this.", however I'd like to be able to get to those constructor properties from anywhere inside the class.

Example:
class CoffeeScriptClass
  constructor: (@foo) ->

  _sampleFunction: ->
    $.each BigArray, (index, NestedArray) ->
      $.each NestedArray, (index, widget) ->

        ## I'd like @foo to reference the constructor value

        widget = @foo 

        return
      return  
    return
Does this make sense? I'm really trying to keep my OO Javascript tidy and organized, but I'm having a difficult time with the scoping part of coffeescript. I'll happily welcome any refactoring/advice on the rest of my class. Thanks all.
解决方案
You need to scope the inner functions:
class CoffeeScriptClass
  constructor: (@foo) ->

  _sampleFunction: ->
    $.each BigArray, (index, NestedArray) => // keep parent scope
      $.each NestedArray, (index, widget) => // keep parent scope

        ## I'd like @foo to reference the constructor value

        widget = @foo 

        return
      return  
    return




Here is the compiled JS showing why this works:
var CoffeeScriptClass;

CoffeeScriptClass = (function() {

  function CoffeeScriptClass(foo) {
    this.foo = foo;
  }

  CoffeeScriptClass.prototype._sampleFunction = function() {

    var _this = this; // reference to the class is maintained

    $.each(BigArray, function(index, NestedArray) {
      $.each(NestedArray, function(index, widget) {
        widget = _this.foo;
      });
    });
  };

  return CoffeeScriptClass;

})();


                        
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