04803-medium-trim-right.ts

// ============= Test Cases =============
import type { Equal, Expect } from "./test-utils";

type cases = [
  Expect<Equal<TrimRight<"str">, "str">>,
  Expect<Equal<TrimRight<"str ">, "str">>,
  Expect<Equal<TrimRight<"str     ">, "str">>,
  Expect<Equal<TrimRight<"     str     ">, "     str">>,
  Expect<Equal<TrimRight<"   foo bar  \n\t ">, "   foo bar">>,
  Expect<Equal<TrimRight<"">, "">>,
  Expect<Equal<TrimRight<"\n\t ">, "">>
];

// ============= Your Code Here =============
type Space = " " | "\n" | "\t";
type TrimRight<S extends string> = S extends `${infer R}${Space}`
  ? TrimRight<R>
  : S;