A simple class for manipulating key/value pairs, and applying associated callbacks.

dataModel.coffee

class DataModel
  constructor: () ->
    @data = {}
    @callbacks =
      set: []
      unset: []
    return

  applyCallbacks: (action, args) ->
    for cb in @callbacks[action]
      cb.apply `undefined`, args  if typeof cb is "function"
    return

  appendCallback: (action, callback) ->
    @callbacks[action].push callback  if @callbacks[action] isnt `undefined`
    return

  removeCallback: (action, callback) ->
    for cb in @callbacks[action]
      cb = @callbacks[action][i]
      @callbacks[action].splice i, 1  if cb is callback
    return

  set: (key, value) ->
    @data[key] = value
    @applyCallbacks "set", [
      key
      value
    ]
    return

  unset: (key) ->
    if @data[key] isnt `undefined`
      delete @data[key]
      @applyCallbacks "unset", [key]
    return

  get: (key) ->
    @data[key]

  getAll: ->
    @data