CoffeeScript Mixin Class. Extend it to create mixin functionality.

gistfile1.txt

class Mixin
  @mixin: (Klass)->
    # Class methods
    Klass[key] = val for key, val of @ when key != 'mixin'
    # Instance methods
    Klass::[key] = val for key, val of @prototype

class Extra extends Mixin
  @fn: -> alert 'class fn called'
  fn: -> alert 'instance fn called'  

class Base
  baseClassFn: -> 'baseClassFn called'
  baseInstancefn: -> 'baseInstanceFn called'
 
Extra.mixin Base
 
Base.fn() #'class fn' alerted
b = new Base
b.fn() #'instance fn' alerted


# Also, you can use this right in the class definition!
class Base2
  Extra.mixin @
  baseClassFn: -> 'baseClassFn called'
  baseInstancefn: -> 'baseInstanceFn called'
 
 
Base2.fn() #'class fn' alerted
b2 = new Base2
b2.fn() #'instance fn' alerted