A RxJs operator that runs in a new thread. https://github.com/deebloo/rxjs-worker

rxjs-worker-map.example.js

// https://github.com/deebloo/rxjs-worker
var observable = Observable.of([0, 1, 2, 3, 4]);

observable
  .map(function (data) {
    return data.concat([5, 6, 7, 8, 9]);
  })
  .workerMap(function (data) {
    return data.concat([10,11,12,13,14]);;
  })
  .subscribe(function (data) {
    console.log(data);
  });

rxjs-worker-map.operator.js

// https://github.com/deebloo/rxjs-worker
(function (Rx) {
  
  Rx.Observable.prototype.workerMap = workerMap;

  function workerMap(cb) {
    var subject = new Rx.Subject();
    var worker = _createWorker(cb);
  
    worker.onmessage = function (e) {
      subject.next(e.data);
    }
  
    this.subscribe(function (value) {
      worker.postMessage(value);
    });
  
    return subject;
  }
  
  function _createWorker(fn) {
    var blob = new Blob(
      [
        'self.cb = ', fn.toString(), ';',
        'self.onmessage = function (e) { self.postMessage(self.cb(e.data)) }'
      ],
      { type: 'text/javascript' }
    );
  
    var url = URL.createObjectURL(blob);
  
    return new Worker(url);
  }

})(Rx);