Spine plugin for dirty model attributes

spine.model.dirty.coffee

Include =
  savePrevious: ->
    @constructor.records[@id].previousAttributes = @attributes()

Spine.Model.Dirty =
  extended: ->
    @bind 'refresh', ->
      @each (record) -> record.savePrevious()

    @bind 'save', (record) ->
      if record.previousAttributes?
        for key in record.constructor.attributes when key of record
          if record[key] isnt record.previousAttributes[key]
            record.trigger('change:'+key, record[key])
      record.savePrevious()

    @include Include

###
Usage example:

class Model extends Spine.Model
  @configure "Model", "firstname", "lastname"
  @extend Spine.Model.Dirty

class Controller extends Spine.Controller
  constructor: ->
    Model.bind "change:lastname", (model, lastname) =>
      @log model, lastname