SimpleEventEmitter.ls

class SimpleEventEmitter:
  _events: []

  _onceWrapper: (type) ->
    wrapper = ~>
      @off(type, wrapper)
      fn.apply(this, arguments)

  on: (type, fn, once=false) !->
    @_events[type] = @_events[type]? or []
    if once
      @_events[type].push(@_onceWrapper(type)(fn))
    else
      @_events[type].push(fn)

  once: (type, fn) !->
    @on(type, fn, true)

  off: (type, fn) !->
    for event, i in @_events[type]? or []
      if event.toString! in [fn.toString!, @_onceWrapper(type)(fn)]
        @_events.splice(i, 1)

  emit: (type) !->
    args = Array.prototype.slice.call(arguments)
    args.shift!
    for event in @_events[type]? or []
      event.apply(this, args)


EventEmitter.addListener = EventEmitter.on
EventEmitter.removeListener = EventEmitter.off
EventEmitter.trigger = EventEmitter.emit

module.exports = SimpleEventEmitter