worker.js

/**
 * Copyright 2017 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *     http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

importScripts("https://unpkg.com/comlink/dist/umd/comlink.js");
// importScripts("../../../dist/umd/comlink.js");

const obj = {
  counter: 0,
  inc() {
    this.counter++;
  },
};

/**
 * When a connection is made into this shared worker, expose `obj`
 * via the connection `port`.
 */
onconnect = function (event) {
  const port = event.ports[0];

  Comlink.expose(obj, port);
};

// Single line alternative:
// onconnect = (e) => Comlink.expose(obj, e.ports[0]);