TypeScript generic recursive memoization

memoize.ts

function memoize<Args extends unknown[], R>(f: (...args: Args) => R): (...args: Args) => R {
  const cache = new Map();
  let retCache: { value: R } | undefined;
  return (...args: Args): R => {
    if (args.length > 0) {
      if (!cache.has(args[0])) {
        cache.set(args[0], memoize((...restArgs) => (f as any)(args[0], ...restArgs)));
      }
      return cache.get(args[0])(...args.slice(1));
    }
    if (!retCache) retCache = { value: f(...args) };
    return retCache.value;
  };
}