A bookmarklet to save an image opening on Twitter

bookmarklet.js

javascript:(async()=>{var[,t,e]=location.href.match(/\/status\/(\d+)\/photo\/(\d)/),a=document.querySelector('div[style*="transition-duration:"][style*="background-color:"]'),i=[...a.querySelectorAll("ul")].find(t=>[...t.style].includes("transform")),o='img[src^="https://pbs.twimg.com/media/"]',i=(void 0!==i?[...i.querySelectorAll(o)][e-1]:[...a.querySelectorAll(o)].find(t=>"tweetPhoto"!==t.parentNode.getAttribute("data-testid"))).src,a=await fetch(i).then(t=>t.blob()),o=a?.type;/^image\/.+$/.test(o)&&(await(i=await(await window.showSaveFilePicker({startIn:"downloads",suggestedName:`twitter_${t}_`+e,types:[{accept:{[o]:"."+o.match(/image\/(.+)/)[1]}}]})).createWritable()).write(a),await i.close())})();

save-twitter-image.js

(async () => {
  const url = location.href;
  const [_, tweetId, nth] = url.match(/\/status\/(\d+)\/photo\/(\d)/);

  const modal = document.querySelector('div[style*="transition-duration:"][style*="background-color:"]');
  const ul = [...modal.querySelectorAll('ul')].find((elm) => [...elm.style].includes('transform'));
  const imgQuery = 'img[src^="https://pbs.twimg.com/media/"]';
  const img = ul !== undefined ?
    [...ul.querySelectorAll(imgQuery)][nth - 1] :
    [...modal.querySelectorAll(imgQuery)].find((elm) => elm.parentNode.getAttribute('data-testid') !== 'tweetPhoto');
  const imgUrl = img.src;

  const blob = await fetch(imgUrl).then((res) => res.blob());
  const blobType = blob?.type;

  if (!/^image\/.+$/.test(blobType)) {
    return;
  }

  const fileSystemFileHandle = await window.showSaveFilePicker({
    startIn: 'downloads',
    suggestedName: `twitter_${ tweetId }_${ nth }`,
    types: [
      {
        accept: {
          // Twitterの画像はJPEG、PNG、GIFだけだった気がするから拡張子はこれでも問題ないはず
          [blobType]: `.${ blobType.match(/image\/(.+)/)[1] }`,
        },
      },
    ],
  });

  const writableStream = await fileSystemFileHandle.createWritable();
  await writableStream.write(blob);
  await writableStream.close();
})();