loosen.ts

/**
 * ["a", "b", "c"] => ["a" | "b" | "c", "a" | "b" | "c", "a" | "b" | "c"]
 *
 * Assumes keys are unique
 */
export type LoosenTuple<
  Arr extends readonly any[],
  OriginalArr extends readonly any[] = Arr,
> = Arr extends readonly [unknown, ...infer Tail]
  ? readonly [OriginalArr[number], ...LoosenTuple<Tail, OriginalArr>]
  : readonly []