TypeScript type-safe string replace and replaceAll (doesn't support regex) using template literal types (note: this is just a proof of concept and shouldnt be taken seriously)

replace-replaceAll.ts

type Replace<
  T extends string,
  Match extends string,
  Replacement extends string
> = T extends `${infer Prefix}${Match}${infer Postfix}`
  ? `${Prefix}${Replacement}${Postfix}`
  : never;

type ReplaceAll<
  T extends string,
  Match extends string,
  Replacement extends string
> = T extends `${infer Prefix}${Match}${infer Postfix}`
  ? `${Prefix}${Replacement}${ReplaceAll<Postfix, Match, Replacement>}`
  : T;