Deep convert function with converted types

convert.ts

type Converted<T, TOriginal, TNew> = T extends TOriginal
  ? TNew
  : T extends Array<infer U>
  ? Converted<U, TOriginal, TNew>[]
  : T extends object
  ? { [K in keyof T]: Converted<T[K], TOriginal, TNew> }
  : T;

function convert<T, TOriginal, TNew>(
  value: T,
  predicateFn: (value: any) => value is TOriginal,
  converterFn: (value: TOriginal) => TNew,
): Converted<T, TOriginal, TNew> {
  if (predicateFn(value)) {
    return converterFn(value) as Converted<T, TOriginal, TNew>;
  }

  if (Array.isArray(value)) {
    return value.map((item) =>
      convert(item, predicateFn, converterFn),
    ) as Converted<T, TOriginal, TNew>;
  }

  if (value && typeof value === "object") {
    return Object.fromEntries(
      Object.entries(value).map(([key, value]) => [
        key,
        convert(value, predicateFn, converterFn),
      ]),
    ) as Converted<T, TOriginal, TNew>;
  }

  return value as Converted<T, TOriginal, TNew>;
}