Which data put in jwt-tokens (node.js + mongoose)?

Question

Sorry for bad English. To generate JWT-token i'm using

jwt     = require('jsonwebtoken');
/* some code */

//function to create jwt-token
function createToken(user) {
  return jwt.sign(user, config.secret, { expiresIn: 60*60*5 });
}

/* some code */

//after registration/authorization (if success) createToken token function is calling
createToken(user);

I would like to learn the best practices, what data must be passed to a function to create the token. For example, can this be as:
login (John) and id( ObjectId("5821d94dbb021a1360582da3") when using MongoDb)?
And here, I think, will be relevant question:
If I store in token some information that allows initialize user, I can pull its data from the database. Is this correct, initialize the user from authorization header from JWT? For initialization I'm using express-jwt , which, if successful, sets req.user ? Thanks.

Answer 1

you can put the generated token in browser local storage, if you are using browser. You can also store session values in the token itself, those values will be decoded on the server side by nodejs.