Get Youtube raw video or audio url

file.js

(async () => {
  const html = await fetch(window.location.href).then((resp) => resp.text()).then((text) => text);
  const startStr = 'ytplayer.config = {';
  const start = html.indexOf(startStr) + startStr.length - 1;
  const end = html.indexOf('};', start) + 1;
  const playerObj = JSON.parse(html.slice(start, end));

  playerObj.args.player_response = JSON.parse(playerObj.args.player_response);

  const videoUrls = playerObj.args.player_response.streamingData.adaptiveFormats.reduce((acc, item) => {
    if (!acc[item.quality]) {
      acc[item.quality] = {};
    }

    const mimeType = item.mimeType.split(';')[0];

    acc[item.quality][mimeType] = item;

    return acc;
  }, {});

  console.log('!!', videoUrls);
})();