In-Line Worker

makeWorker.js

var makeWorker = function (fn) {
      var blobURL = URL.createObjectURL(
        new Blob(
          [ '(', fn.toString(), ')()' ],
          { type: 'application/javascript' }
        )
      ),
      worker = new Worker(blobURL);
  
      return worker;
    },
    worker = makeWorker(function () {
      postMessage('ready and wating...');
  
      onmessage = function (evt) {
        debugger;
      };
    });

worker.onmessage = function (evt) {
  console.debug('main', evt);
};