Cote.js (promise) in Express

Hi! I’m trying to use cote.js in my express app. Here my route code:

...
router.get('uuid', (req, res, next) => mainSvc.getUuid()
        .then( data => res.json(data) )
        .catch( next )
);

Here mainSvc code:

const      cote = require('cote'),
  uuidRequester = new cote.Requester({ name: 'uuid requester' });

module.exports = {
...
  getUuid:  ()=> {
       const  request = { type: 'uuid' };
        
       return  uuidRequester.send( request )
            .then( data  => {
                console.log('Data:', data);
                return  data;
            })
            .catch( err => {
                console.error('Error:',  err);
                return  Promise.reject( err );
            })
       ;
  }
...
};

Here my service to generate uuid:

const   uuid = require('uuid/v4'),
        cote = require('cote'),
   responder = new cote.Responder({ name: 'uuid responder' });

responder.on('uuid', (res, cb) => {
    cb({ uuid: uuid() });
});

And in console I got error:

uuid requester > service.online uuid responder#47cdd6ce-ccfb-4043-bcf7-e01b54b1b626 on 8000 Error: { uuid: ‘e917380b-8128-4bd7-b087-3ed136987289’ }

Error

What I did wrong and why I got Error instead Data? Thanks

[dashersw]

@Keramet hello! Actually, it’s pretty simple. If you are using promises and callbacks together, you should make sure the first argument in the callback is the error object and it will be passed onto the catch handler, and the second argument is the actual result.

In your case, a simple cb(null, { uuid: uuid() }); would work. On the other hand, you can also use responder.on('uuid', (res) => Promise.resolve({ uuid: uuid() })).

[robophil]

@dashersw I think this should be highlighted more in the readme 😃