setter.coffee

class MyClass extends Layer
	constructor: (options = {}) ->
        
		super options
        
		@_isRightEnough = @x > 200
		@onIsRightEnough = -> null
        
		@on "change:x", ->
			isRightEnough = @x > 200
			return if isRightEnough is @_isRightEnough
            
			@_isRightEnough = isRightEnough
			@emit "change:isRightEnough", @_isRightEnough, @
			@onIsRightEnough(@_isRightEnough)
    
myInstance = new MyClass

myInstance.onIsRightEnough = (bool) -> print bool

myInstance.draggable.enabled = true