Classes within Coffeescript 'Namespace'

问题:

I found this snippet on the Coffeescript FAQ for creating simplistic namespaces ..

# Code:
#
namespace = (target, name, block) ->
  [target, name, block] = [(if typeof exports isnt 'undefined' then exports else window), arguments...] if arguments.length < 3
  top    = target
  target = target[item] or= {} for item in name.split '.'
  block target, top

# Usage:
#
namespace 'Hello.World', (exports) ->
  # `exports` is where you attach namespace members
  exports.hi = -> console.log 'Hi World!'

namespace 'Say.Hello', (exports, top) ->
  # `top` is a reference to the main namespace
  exports.fn = -> top.Hello.World.hi()

Say.Hello.fn()  # prints 'Hi World!'

That is all well and good, but I am having a great deal of trouble doing this with the class keyword. Such that ..

namespace 'Project.Something', (exports) ->
   exports.something = -> class something
    // .. code here
   exports.somethingElse = class somethingElse extends something

can anyone shed some light on the syntax that would accomplish this?

回答1:

The trick is to create the class first

class MyFirstClass
  myFunc: () ->
    console.log 'works'

class MySecondClass
  constructor: (@options = {}) ->
  myFunc: () ->
    console.log 'works too'
    console.log @options

Then somewhere near the end of the file export all the classes than need to be exposed.

namespace "Project.Something", (exports) ->
  exports.MyFirstClass = MyFirstClass
  exports.MySecondClass = MySecondClass

Later on you can use the classes as so:

var firstClass = new Project.Something.MyFirstClass()
firstClass.myFunc()

var secondClass = new Project.Something.MySecondClass 
  someVar: 'Hello World!'

secondClass.myFunc()

回答2:

Even better, the class syntax allows for the name to actually be in the form of a member, so you can actually just do:

namespace 'Secrets', (exports) ->
  class exports.Hello
    constructor: ->
      @message = "Secret Hello!"

a = new Secrets.Hello
console.log a.message

Full fiddle here: http://jsfiddle.net/7Efgd/1/

回答3:

How about using something like this?

module =
    Hello: class Hello extends Backbone.Model
        constructor: ->
            @message = 'Hello'

    Hello2: class Hello2 extends Backbone.View
        constructor: ->
            @message = 'Hello2'