auto-scroll.js

(function () {
  // type in console: allow pasting
  if (window.__shortsAutoScroll) {
    console.log('Auto-scroll already running.');
    return;
  }
  window.__shortsAutoScroll = true;

  let lastTime = 0;
  let hasScrolled = false;

  function getActiveVideo() {
    const videos = document.querySelectorAll('video');
    for (const v of videos) {
      const rect = v.getBoundingClientRect();
      if (rect.height > 0 && rect.top >= 0 && rect.top < window.innerHeight) {
        return v;
      }
    }
    return null;
  }

  function scrollToNextShort() {
    document.dispatchEvent(new KeyboardEvent('keydown', {
      key: 'ArrowDown',
      code: 'ArrowDown',
      keyCode: 40,
      which: 40,
      bubbles: true
    }));
  }

  setInterval(() => {
    const video = getActiveVideo();
    if (!video || !video.duration) return;

    const t = video.currentTime;

    if (lastTime > video.duration - 0.5 && t < 0.5 && !hasScrolled) {
      hasScrolled = true;
      console.log('Short finished once — scrolling to next.');
      scrollToNextShort();
    }

    if (t > 1) {
      hasScrolled = false;
    }

    lastTime = t;
  }, 200);

  console.log('Shorts auto-scroll-on-complete is active.');
})();