Can this coffeescripts method be simplified?

Question

I'm new to coffeescripts. Can the getSum method be simplified more? Thanks

MyObject =
  checkCondition: (num) ->
    return true if num is 5

  getSum: (num) ->
    total = 0
    total += i for i in [1..num] when @checkCondition i
    total

I tried removing the last total but coffeescripts compiler goes nut :-/

Any help greatly appreciate.

Answer 1

First, return true if num is 5 is the same as just num is 5.
Then, you can convert the explicit loop into a reduce (you can read about it in Wikipedia or MDN):

MyObject =
  checkCondition: (num) -> num is 5

  getSum: (num) ->
    [0..num].reduce (x,y) =>
        if @checkCondition y then x + y else x

Note => instead of plain -> after (x,y). This is fat arrow, it prevents the capture of @ the inside function.

Answer 2

As written getSum will only ever return 0 or 5, but I assume this checkCondition is merely an example, so here is my answer:

MyObject =
  checkCondition: (num) -> num is 5

  getSum: (num) ->
    total = (i for i in [1..num] when @checkCondition i).reduce ((x, y) -> x + y), 0

Answer 3

It's not clear what you're trying to achieve here.

The getSum method looks fine. The checkCondition is overcomplicated: it better be checkCondition: (num) -> num is 5