chromium/chrome/test/data/extensions/declarative_net_request/fetch_from_shared_worker.js

// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

self.onconnect = async e => {
  const port = e.ports[0];
  port.onmessage = async msg => {
    try {
      const response = await fetch(msg.data.url);
      if (!response.ok) {
        port.postMessage('bad response');
        return;
      }
      port.postMessage(response.url);
    } catch (error) {
      port.postMessage(`${error.toString()}`);
    }
  };
};