utility function for working with inline web workers

worker.js

function $worker() {
  var workers = [];

  // PUBLIC_API
  return {
    create: create,
    runAll: runAll,
    terminateAll: terminateAll,
    list: list
  }

  /**
   * create a new worker instance and saves it to the list
   * 
   * @param {Function} fn - the function to run in the worker 
   */
  function create(fn) {
    var newWorker = _createWorker(fn);

    workers.push(newWorker);

    return newWorker;
  }

  /**
   * run all of the workers in the array and resolve all
   */
  function runAll(data) {
    var promises = workers.map(function (worker) {
      return worker.run(data);
    });

    return Promise.all(promises);
  }

  /**
   * terminate all workers
   */
  function terminateAll() {
    workers.forEach(function (worker) {
      worker._shell.terminate();
    });

    workers.length = 0;
  }

  /**
   * returns the list of current workers
   */
  function list() {
    return workers;
  }

  /**
   * Create an actual web worker from an object url from a blob
   * 
   * @param {Function} fn - the function to be put into the blog array.
   */
  function _createWorker(fn) {
    var blob = new Blob(['self.onmessage = ', fn], { type: 'text/javascript' });

    return {
      // the web worker instance
      _shell: new Worker(window.URL.createObjectURL(blob)),

      // run the web worker
      run: function (data) {
        return __run(this._shell, data);
      },

      // terminate the web worker
      terminate: function () {
        return __terminate(this);
      }
    };
  }

  /**
   * run the passed in web worker
   */
  function __run(worker, data) {
    data = data || {};

    worker.postMessage(data);

    var promise = new Promise(function (resolve, reject) {
      worker.onmessage = resolve;

      worker.onerror = reject;
    });

    return promise;
  }

  /**
   * terminate the web worker;
   */
  function __terminate(ref) {
    workers.splice(workers.indexOf(ref), 1);

    return ref._shell.terminate();
  }
}