Ticketek—purchasing tickets

ticketek.js

// Do not forget to use your own selectors

const trySelecting = async () => {
  const delay = (timeoutMs = 100) => new Promise((resolve, _reject) => {
    setTimeout(resolve, timeoutMs);
  });

  const findEl = async ({ parent, query, retries, delayBetweenRetriesMs }) => {
    let el = null;
    let attempts = 0;
    do {
      el = (parent ?? document).querySelector(query);
      attempts++;
      await delay(delayBetweenRetriesMs ?? 50);
    } while (el == null && attempts <= (retries ?? 10))

    return el;
  };
  
  const playTada = () => {
    const AudioContext = window.AudioContext || window.webkitAudioContext;
    const audioCtx = new AudioContext();

    const frequencies = [523.25, 659.25, 783.99, 1046.50]; // C5, E5, G5, C6
    const duration = 0.2;

    frequencies.forEach((frequency, index) => {
      const oscillator = audioCtx.createOscillator();
      const gainNode = audioCtx.createGain();

      oscillator.connect(gainNode);
      gainNode.connect(audioCtx.destination);

      oscillator.type = 'triangle';
      oscillator.frequency.setValueAtTime(frequency, audioCtx.currentTime + index * duration);

      gainNode.gain.setValueAtTime(0, audioCtx.currentTime + index * duration);
      gainNode.gain.linearRampToValueAtTime(1, audioCtx.currentTime + index * duration + 0.05);
      gainNode.gain.linearRampToValueAtTime(0, audioCtx.currentTime + (index + 1) * duration);

      oscillator.start(audioCtx.currentTime + index * duration);
      oscillator.stop(audioCtx.currentTime + (index + 1) * duration);
    });
  };

  const retry = () => {
    setTimeout(() => trySelecting(), Math.floor(Math.random() * 4900 + 100));
  };

  await delay();
  const ticketQuanity = await findEl({ query: '#quantity-MCARDPRE-1449038' });
  console.log('ticketQuanity', ticketQuanity);

  // Resetting
  await delay();
  ticketQuanity.value = '0';
  ticketQuanity.dispatchEvent(new Event('change', { bubbles: true }));
  await delay();
  ticketQuanity.value = '1';
  ticketQuanity.dispatchEvent(new Event('change', { bubbles: true }));

  // Clicking the button
  await delay();
  const nextButton = await findEl({ query: '#ticket-selection-page-next-button' });
  console.log('nextButton', nextButton);
  if (nextButton == null) {
    retry();
    return;
  }

  await delay();
  nextButton.click();

  await delay();
  const noTickets = await findEl({ query: '#continueBar > ul.alert-error' });
  console.log('noTickets', noTickets);
  if (noTickets != null) {
    retry();
    return;
  } else {
    playTada();
  }
};

trySelecting();

Do not forget to use your own selectors