Scala Option in CoffeeScript

gistfile1.coffee

Array::filter = (f) -> (x for x in @ when f(x))
Number::filter = (f) -> [@.valueOf()].filter f
String::filter = Number::filter
Object::filter = (f) -> if f(@) then @ else null

Array::foreach = (f) -> (f(x) for x in @)
Number::foreach = (f) -> [@.valueOf()].foreach f
String::foreach = Number::foreach
Object::foreach = (f) -> if @ then f(@) else null

Array::exists = (f) -> (
  for item in @
    if f(item) then return true
  false
)
Number::exists = (f) -> [@.valueOf()].exists f
String::exists = Number::exists
Object::exists = (f) -> f(@)

Array::map = (f) -> ((f(x) for x in @))
Number::map = (f) -> [@.valueOf()].map f
String::map = Number::map
Object::map = (f) -> if @ then f(@) else null


class MyOption
  constructor: (@item) ->
  getOrElse: (def) -> if @item? then @item else def
  exists: (f) -> @item?.exists f
  get: -> @item
  isDefined: -> @item?
  isEmpty: -> !@item?
  filter: (f) -> @item?.filter f
  foreach: (f) -> @item?.foreach f
  map: (f) -> @item?.map f
  orElse: (def) -> if @item? then @ else def
  orNull: -> if @item? then @ else null


Option = (x) -> new MyOption(x)


$ ->
  x = "Yes"
  y = null
  alert Option(x).getOrElse("No")
  alert Option(y).getOrElse("No")