Cloudflare worker to inline scripts

inliner.js

addEventListener('fetch', event => {
  event.respondWith(handleRequest(event.request))
})

/**
 * Respond to the request
 * @param {Request} request
 */
async function handleRequest(request) {
  const resp = await fetch(request);
  const body = await resp.clone().text();

  const remoteScripts = [];
  body.replace(/src="(.*)"/g, (_, src) => {
    remoteScripts.push(src);
  });
  const remoteScriptsSources = await Promise.all(
    remoteScripts.map(async origSrc => {
      let src = origSrc;
      if (src.startsWith('//')) {
        src = 'https:' + src;
      }
      return [origSrc, await (await fetch(src)).text()];
    })
  );
  const scriptMap = remoteScriptsSources.reduce((acc, [src, body]) => {
    acc[src] = body;
    return acc;
  }, {});

  return new HTMLRewriter()
    .on('script[src]', {
      element(elem) {
        const src = elem.getAttribute('src');
        if (!(src in scriptMap)) {
          console.warn(`${src} not in ${Object.keys(scriptMap)}`);
          return;
        }
        elem.removeAttribute('src');
        elem.removeAttribute('crossorigin');
        elem.setAttribute('data-inlined-from', src);
        elem.append(scriptMap[src], {html: true});
      }
    })
    .transform(resp.clone());
}