FromStream.js

Rx.Observable.asStream = function (ev) {
    return Rx.Observable.create(function (obs) {

        function handler (data) {
          obs.onNext(data); // Call as many times with onNext to yield new data
          // obs.onCompleted(); // optional to signal the end of the stream
        }

        ev.on('data', handler);

        // Can handle errors too
        function errHandler (e) { 
          obs.onError(e);
        }
          
        ev.on('error', errHandler);

        // When disposing, clean up
        return function () {
          ev.off(name, handler);
          ev.off('error', errHandler);
        };
    };
};

// Filtering
var rxStream = Rx.Observable.asStream(stream)
  .filter(function (x) { /* whatever predicate you wish */ });

var handle = rxStream.subscribe(function (x) {
    // Handle values
}, function (err) {
    // Handle errors
});

// Clean up the handles which removes the event listeners
handle.dispose();