Simple Deferred with CoffeeScript.

SimpleDeferred.coffee

class Disposal
    constructor: ->
    dispose: ->
        @el?.parentNode?.removeChild @el
        @el = null
        @off?()
        @disposeInternal.apply @, arguments

    disposeInternal: ->
    
# ----------------------------------------------

class Deferred extends Disposal
    constructor: ->
    resolve: (val) ->
        done?.call @, val for done in @_doneHandlers if @_doneHandlers
        return @

    done: (func) ->
        (@_doneHandlers or (@_doneHandlers = [])).push func if func
        return @

    fail: (func) ->
        (@_failHandlers or (@_failHandlers = [])).push func if func
        return @

    disposeInternal: ->
        @_doneHandlers = null

class When extends Disposal
    constructor: (defList...) ->
        @def = new Deferred

        len = defList.length
        _done = =>
            --len or @def.resolve()

        def.done _done for def in defList

    done: (func) ->
        @def.done func
        return @

    fail: (func) ->
        @def.fail func
        return @

    disposeInternal: ->
        @def.dispose()
        @def = null