For those interested in knowing how Option and Result works, here is concise summary

I’m gonna rename Option as Maybe and Result as Either and we gonna have an implementation for map/fmap as well

```
open Belt
type maybe<'a> = Just('a) | Nothing
let maybeMap =
(ma: maybe<'a>, f: 'a => 'b) => {
switch ma {
| Just(a) => Just(f(a))
| _ => Nothing
}
}
let j1 = Just(1)
let n1 = Nothing
let mj1 = maybeMap(j1, x => Int.toString(x))
let mn1 = maybeMap(n1, x => Int.toString(x))
Js.log(j1) // { _0: 1 }
Js.log(n1) // 0
Js.log(mj1) // { _0: '1' }, here we can see that the value was mapped
Js.log(mn1) // 0
type either<'a, 'b> = Left('a) | Right('b)
let eitherMap =
(ma: either<'a, 'b>, f: 'b => 'c) => {
switch ma {
| Right(a) => Right(f(a))
| Left(a) => Left(a)
}
}
let r1 = Right(1)
let l1 = Left(1)
let mr1 = eitherMap(r1, x => Int.toString(x))
let ml1 = eitherMap(l1, x => Int.toString(x))
Js.log(r1) // { TAG: 1, _0: 1 }
Js.log(l1) // { TAG: 0, _0: 1 }
Js.log(mr1) // { TAG: 1, _0: '1' }, here we can see that the value was mapped
Js.log(ml1) // { TAG: 0, _0: 1}
```