RxJS stream from SuperAgent request

Rx.Observable.fromSuperagent.es6

let Rx = require("rx");

Rx.Observable.fromSuperagent = request => () => Rx.Observable.create(observer => {
    request.end((err, res) => {
        if (err) {
            observer.onError(err)
        } else {
            observer.onNext(res);
        }
        observer.onCompleted();
    })
});

rx.superagent.js

Rx.Observable.fromSuperagent = function(req){
    return Rx.Observable.create(function(observable){
       req.end(function(err, res){
           if(err){
               observable.onError(err);
           } else {
               observable.onNext(res);
           }
           observable.onCompleted();
       })
    });
};

Usage example:

let responseStream = requestStream.map(url => {
        return Rx.Observable.fromSuperagent(request.get(url));
}).concatAll();