02070-medium-drop-char.ts

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

type cases = [
    // @ts-expect-error
    Expect<Equal<DropChar<"butter fly!", "">, "butterfly!">>,
    Expect<Equal<DropChar<"butter fly!", " ">, "butterfly!">>,
    Expect<Equal<DropChar<"butter fly!", "!">, "butter fly">>,
    Expect<Equal<DropChar<"    butter fly!        ", " ">, "butterfly!">>,
    Expect<Equal<DropChar<" b u t t e r f l y ! ", " ">, "butterfly!">>,
    Expect<
        Equal<DropChar<" b u t t e r f l y ! ", "b">, "  u t t e r f l y ! ">
    >,
    Expect<Equal<DropChar<" b u t t e r f l y ! ", "t">, " b u   e r f l y ! ">>
];

// ============= Your Code Here =============

type DropChar<S, C> = S extends `${infer First}${infer Rest}`
    ? First extends C
        ? DropChar<Rest, C>
        : `${First}${DropChar<Rest, C>}`
    : S;