How does Passport.js handle JWT authentication?

How does Passport.js handle JWT authentication?

Passport.js uses strategies to authenticate requests. For JWT, it verifies the token and extracts user info.

What are the steps to set it up?

First, install the necessary packages, then configure Passport with a JWT strategy and set up routes.

Can you show me a code example?

Sure! Here's a basic example:

const JwtStrategy = require('passport-jwt').Strategy;
const ExtractJwt = require('passport-jwt').ExtractJwt;

const opts = {
  jwtFromRequest: ExtractJwt.fromAuthHeaderAsBearerToken(),
  secretOrKey: 'your_jwt_secret',
};

passport.use(new JwtStrategy(opts, (jwt_payload, done) => {
  User.findById(jwt_payload.id)
    .then(user => {
      return done(null, user);
    })
    .catch(err => done(err, false));
}));

What should I do if the token is invalid?

If the token is invalid, you should return a 401 Unauthorized response and prompt the user to log in again.