chromium/chrome/test/data/extensions/api_test/shared_worker/basic/worker.js

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

self.addEventListener('connect', function(e) {
  var port = e.ports[0];
  port.start();
  port.postMessage('hullo there!');
});