Function wrapper

src/util/regex.ts:16–25

(arg: T)

  const cache: Map<T, U> = new Map();

  function wrapper(arg: T): U {
    let cachedValue: U | undefined = cache.get(arg);

    if (cachedValue == null) {
      cachedValue = func(arg);
      cache.set(arg, cachedValue);
    }

    return cachedValue;
  }

  return wrapper;
}