export const once = <T extends (...args: unknown[]) => unknown>(fn: T) => {
  let called = false;
  let value: ReturnType<T>;
  return (...args: Parameters<T>): ReturnType<T> => {
    if (!called) {
      called = true;
      value = fn(...args) as ReturnType<T>;
    }
    return value;
  };
};

// Usage
const initialize = once(() => {
  console.log('Initializing...');
  return { ready: true };
});

initialize(); // Initializing... { ready: true }
initialize(); // { ready: true } (cached, no log)