iterator

iterator.coffee

i = Iterator ->
  x = 0
  @yield x # 0
  x += 10
  @yield x # 10
  x += 10
  if no
    @yield "skipped"
  else if yes
    @yield x
  x += 10
  @yield x # 30

i.next() #=>  0
i.next() #=> 10
i.next() #=> 20
i.next() #=> 30
i.next() #=> null

replaced.coffee

i = Iterator ->
  [x] = []
  [
    =>
      x = 0
      @yield x
    =>
      x += 10
      @yield x
    =>
      x += 10
      if no
        @yield "skipped"
      else if yes
        @yield x
    =>
      x += 10
      @yield x
  ]

i.next() #=>  0
i.next() #=> 10
i.next() #=> 20
i.next() #=> 30
i.next() #=> null