Typescript Odd Number Type

type OddNumber<
X extends number,
Y extends unknown[] = [1],
Z extends number = never
> = Y[‘length’] extends X
? Z | Y[‘length’]
: OddNumber<X, [1, 1, …Y], Z | Y[‘length’]>
type a = OddNumber<1> // 1
type b = OddNumber< 3 > // 1 | 3
type c = OddNumber<5> // 1 | 3 | 5
type d = OddNumber<7> // 1 | 3 | 5 | 7

--

--

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store