A JavaScript implementation of the Rails delegate class method (kind of)

delegator.coffee

class Delegator

  @delegate: []

  constructor: ->
    for delegate in @constructor.delegate
      target = delegate[delegate.length - 1].to
      for attribute in delegate when not attribute.to
        property = {}
        if /\(\)$/.test attribute
          funcName = attribute.substring 0, attribute.length - 2
          @[funcName] = (->
            _funcName = funcName
            ->
              @[target][_funcName]()
          )()

        else
          property[attribute] =
            get: (->
              name = attribute
              ->
                @[target][name]
            )()
          Object.defineProperties @, property

example.coffee

class MyThing extends Delegator

  @delegate: [
    ['foo', to: 'bar']
  ]
  
  constructor: (@bar) ->
    super
    

bar = {foo: 'foobar'}
myThing = new MyThing(bar)
myThing.foo  # 'foobar'

# Anyway, that's the idea of it