utils.ts

// TODO: handle this on the server instead
export function now() {
  const date = new Date();

  return new Date(
    date.getUTCFullYear(),
    date.getUTCMonth(),
    date.getUTCDate(),
    date.getUTCHours(),
    date.getUTCMinutes(),
    date.getUTCSeconds()
  );
}

export function sleep(ms: number) {
  return new Promise((res) => setTimeout(res, ms));
}

// Returns the words (or whatever substrings based on the `separator`)
// in a string up until the point of meeting the`max` character limit
export function shorten(str: string | null, max: number, separator = ' ') {
  if (!str) {
    return '';
  } else if (str.length <= max) {
    return str;
  }

  return str.substr(0, str.lastIndexOf(separator, max)).concat('...');
}

export function shouldActivateGameMode(message: string) {
  if (!message || !message.length) {
    return false;
  }

  return (
    [
      '/play2048',
      '/xyzzy',
      '/poweroverwhelming',
      '/howdoyouturnthison',
      'what is 2^11',
      'what is 2^11?',
      "what's 2^11",
      "what's 2^11?",
    ].indexOf(message.toLowerCase()) !== -1
  );
}

export function throttle<T extends []>(
  callback: (..._: T) => void,
  wait: number,
  immediate = true
): (..._: T) => void {
  let timeout: NodeJS.Timeout | undefined;
  let initialCall = true;

  return (...args: T) => {
    const callNow = immediate && initialCall;

    const next = () => {
      timeout = clearTimeout(timeout) as undefined;
      callback(...args);
    };

    if (callNow) {
      initialCall = false;
      next();
    }

    if (timeout === void 0) {
      timeout = setTimeout(next, wait);
    }
  };
}

export function setupPostMessageHandlers(w: any, handler: (msg: any) => void) {
  const cb = (msg: any) => {
    handler(msg);
  };

  if (w.addEventListener) {
    w.addEventListener('message', cb);

    return () => w.removeEventListener('message', cb);
  } else {
    w.attachEvent('onmessage', cb);

    return () => w.detachEvent('message', cb);
  }
}