typescript range

1// n is your max range
2[...Array(n).keys()]
3
4let n = 10
5[...Array(n).keys()] // [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

1const range = (start, end) => Array.from({length: (end - start)}, (v, k) => k + start);
2

1type PrependNextNum<A extends Array<unknown>> = A['length'] extends infer T ? ((t: T, ...a: A) => void) extends ((...x: infer X) => void) ? X : never : never;
2
3type EnumerateInternal<A extends Array<unknown>, N extends number> = { 0: A, 1: EnumerateInternal<PrependNextNum<A>, N> }[N extends A['length'] ? 0 : 1];
4
5export type Enumerate<N extends number> = EnumerateInternal<[], N> extends (infer E)[] ? E : never;
6
7export type Range<FROM extends number, TO extends number> = Exclude<Enumerate<TO>, Enumerate<FROM>>;