I am learning to be a full stack developer and have been building out an application using Node JS as a backend. Since I have lots of experience using Angular I love RxJS. So naturally I was tempted to use RxJS for some types of tasks. Are there any down sides to using RxJS on the backend, more specifically are there any downs sides I can learn about from the following code implementation?

Im using Sequalize and Postgres. As you can see in the Invite Service I have used the Observable stream to first check if the Invite id is valid and then it checks if the recipient email is found in the database as a current user account or not. From either of the three returned values to the route I can now tell the front end what it must do next.

Other notable things:

1. I am using typical JWT authentication which in this case is a special user in the db since the request is being made from a web app and there is no actual logged in user.

2. I decided to pass the invite id and the recipient email in the headers which I know is kind of unusual.

This web app is actually just a mediator to deal with a complicated invite process which is being initialized from a React Native app.

Entry Point:

import inviteGenRouter from './routes/invite.routes'; let inviteRouter = inviteGenRouter(services); api.use('/invite', inviteRouter);  app.use('/api', [passport.authenticate('jwt-bearer', {   session: false,   failWithError: true }), (err, req, res, next) => {    if (err) {     Logger.error('Authentication Handshake: ', err);     let error = {       error: err.name,       message: err.message     };     let statusCode = err.status || 500;     return res.status(statusCode).json(error);   }   return next(); }], api); 

Invite Routes:

router.route('/').get((req, res) => {   if (req.headers.data) {     return services.InviteService.authenticateInvite(req.headers.data)       .subscribe(         _res => {           // Return options for front end.           // If string the invite code was not found.           // If null the associated email was not a user account.           // If user the associated email was found.         },         _error => {           // Some stuff when wrong...         }       );   } else {     // return some sort of error code.   }  }); 

Invite Service:

class InviteService  {    constructor(models) {     this.models = models   }    findInviteById(id) {     return Observable.defer(() => {       return Observable.fromPromise(this.models.Invite.findOne({         where: { inviteId: id }       }));     });   }    findUserById(email) {     return Observable.defer(() => {       return Observable.fromPromise(this.models.User.findOne({         where: { email: email }       }));     });   }    authenticateInvite(token) {     let payload = jwt.verify(token, appConfig.SESSION_SECRET);      return this.findInviteById(payload.inviteId)       .map(_invite => _invite ? _invite : Observable.of('Invalid Invite ID'))       .mergeMap(_invite => _invite._isScalar ? _invite : this.findUserById(payload.email));   } }  module.exports = InviteService;