ruby-like accessors in coffeescript

accessors.coffee

Function::getter = (name, getter) ->
  getter ?= () -> @["_" + name]
  Object.defineProperty @prototype, name, get: getter, configurable: true

Function::setter = (name, setter) ->
  setter ?= (value) -> @["_" + name] = value
  Object.defineProperty @prototype, name, set: setter, configurable: true

Function::accessor = (name, options) ->
  {get: getter, set: setter, default: value} = options ? {}
  @getter(name, getter)
  @setter(name, setter)
  @::["_" + name] = value if value?

class Person
  @accessor "firstName", default: "foo"
  @accessor "lastName", default: "bar"
  @getter "name", () -> "#{@firstName} #{@lastName}"

person = new Person
console.log(person.name) #=> "foo bar"
person.firstName = "first"
person.lastName = "last"
console.log(person.name) #=> "first last"