Coffeescript和node.js混淆。需要实例化类？ [英] Coffeescript and node.js confusion. require instantiates class?

问题描述

我无法尝试让我的类在我的node.js文件中工作。当我需要我写的模块，require'./module'调用我的构造函数并给出一个错误。但我实际上想在稍后的文件中实例化。

I'm having trouble trying to get my class working in my node.js file. When I require the module I wrote, the require './module' calls my constructor and gives an error. But I actually want to instantiate later on in the file.

即

class Mic

constructor: (x) ->
  @t = []
  @t.push x

exports.Mic = Mic

这里是我的app.coffee文件

and here is my app.coffee file

require 'coffee-script'
require './Mic'

当我运行app.coffee时，它给出一个异常ReferenceError：x未定义。这是有道理的，因为它调用的构造函数，但为什么它调用的构造函数即使我没有调用新的麦克风？

When I run app.coffee it gives an exception ReferenceError: x is not defined. Which makes sense since its calling the constructor, but why is it calling the constructor even though I havent called new Mic ?

编辑
修复缩进后

Edit After fixing the indentation

class Mic
    constructor: (x) ->
        @t = []
        @t.push x

exports.Mic = Mic

并将我的app.coffee更新到

and updating my app.coffee to

Mic = require './Mic'

m = new Mic 3
console.log m

错误

TypeError: object is not a function
    at Object.CALL_NON_FUNCTION_AS_CONSTRUCTOR (native)

推荐答案

第一件事：你不需要 require 'coffee-script' - 使用咖啡就可以了;与运行编译的JavaScript相同。您不需要在程序运行时提供CoffeeScript库。

First thing's first: you don't need the require 'coffee-script'—running it with coffee is enough; same as running the compiled JavaScript. You don't need the CoffeeScript library available at runtime in your program.

其次，第一个文件缩进不正确;如果你想要 Mic 的构造函数，在类下面缩进一级，即：

Secondly, the first file appears indented incorrectly; if you want that to be Mic's constructor, indent it one level underneath the class, i.e.:

class Mic
  constructor: (x) ->
    @t = []
    @t.push x

exports.Mic = Mic

最后，问题是 exports 是导出的对象。请参阅此处：

Finally, the issue is that exports is an object of exports. See here:

exports.Mic = Mic

您已将 Mic 分配给 exports 对象 Mic 键，因此现在Mic.coffee中的 exports 看起来像这样：

You've assigned Mic to the exports object's Mic key, so now exports in Mic.coffee looks like this:

{ Mic: ...your class... }

当你说 require'./Mic'时，你得到那个对象;换句话说：

When you say require './Mic', you're getting that object back; in other words:

require('./Mic') == { Mic: ...your class... }

因此，您需要执行以下操作之一：

So you need to do one of the following:

1. 导出 Mic 作为Mic.coffee的整个导出，而不是键：

1. Export Mic as the entire export of Mic.coffee, and not as a key:

module.exports = Mic

取出整个模块，然后在<：p>

Get the entire module out, and then instantiate the Mic object within:

mic = require './Mic'
m = new mic.Mic 3

只需从 require 模块中取出 Mic ：

{Mic} = require './Mic'  # equivalent to saying Mic = require('./Mic').Mic
m = new Mic 3

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