ridiculously type-safe Array<string>.join()

join.ts

/**
 * Joins a string array together with a given spacer. Ridiculously unecessarily type-safe!
 * @param t The tuple/array of string items to join together
 * @param s The spacer to go between each character
 * @returns A joint string joined together
 */
export function join<V extends string, Tuple extends Readonly<[V, ...V[]]>, Spacer extends string>(
	t: Tuple,
	s: Spacer
) {
	return t.join(s) as JoinStrTuple<Writable<Tuple>, Spacer>;
}

type Writable<T> = {
	-readonly [K in keyof T]: T[K];
};

type JoinStrTuple<
	Tuple extends string[],
	Spacer extends string = ' ',
	Head extends string = ''
> = Tuple extends [infer F, ...infer L]
	? Head extends ''
		? JoinStrTuple<Extract<L, string[]>, Spacer, F & string>
		: JoinStrTuple<Extract<L, string[]>, Spacer, `${Head}${Spacer}${F & string}`>
	: Head;

💀

@pxseu @Phineas hi guys!!!!!!!!!!!!!!!!!!!!