nitter/public/js/embedResize.js

(function() {
  var embedElement = document.querySelector('.embed-wrapper, .tweet-embed, .embed-video');
  if (!embedElement) return;

  var lastHeight = 0;

  function sendHeight() {
    var currentHeight = embedElement.offsetHeight;
    if (currentHeight !== lastHeight) {
      lastHeight = currentHeight;
      window.parent.postMessage(['resizeIframe', { h: currentHeight, url: location.href }], '*');
    }
  }

  // Respond to height requests from parent via MessageChannel
  window.addEventListener('message', function(event) {
    if (event.source === window.parent && event.ports && event.ports[0]) {
      event.ports[0].postMessage(embedElement.offsetHeight);
    }
  });

  window.addEventListener('load', sendHeight);
  new ResizeObserver(sendHeight).observe(embedElement);

  // Expose for embedTweet.js
  window._nitterSendHeight = sendHeight;
})();