app.configure(authentication(settings));
app.configure(jwt());

{
    name: 'jwt', // the name to use when invoking the authentication Strategy
    entity: 'user', // the entity that you pull from if an 'id' is present in the payload
    service: 'users', // the service to look up the entity
    passReqToCallback: true, // whether the request object should be passed to `verify`
    jwtFromRequest: ExtractJwt.fromHeader, // a passport-jwt option determining where to parse the JWT
    secretOrKey: auth.secret, // Your main secret provided to passport-jwt
    session: false // whether to use sessions,
    Verifier: Verifier // A Verifier class. Defaults to the built-in one but can be a custom one. See below for details.
}

{
    constructor(app, options) // the class constructor
    verify(req, payload, done) // queries the configured service
}

import jwt, { Verifier } from '@feathersjs/authentication-jwt';

class CustomVerifier extends Verifier {
  // The verify function has the exact same inputs and 
  // return values as a vanilla passport strategy
  verify(req, payload, done) {
    // do your custom stuff. You can call internal Verifier methods
    // and reference this.app and this.options. This method must be implemented.
    done(null, payload);
  }
}

app.configure(jwt({ Verifier: CustomVerifier }));

// Example of pulling from the body instead
import jwt, { ExtractJwt } from '@feathersjs/authentication-jwt';

app.configure(jwt({ jwtFromRequest: ExtractJwt.fromBodyField('accessToken') }));

{
  strategy: 'jwt',
  accessToken: '<token>'
}

const feathers = require('feathers');
const rest = require('feathers-rest');
const hooks = require('feathers-hooks');
const memory = require('feathers-memory');
const bodyParser = require('body-parser');
const errorHandler = require('feathers-errors/handler');
const auth = require('feathers-authentication');
const jwt = require('@feathersjs/authentication-jwt');

// Initialize the application
const app = feathers()
  .configure(rest())
  .configure(hooks())
  // Needed for parsing bodies (login)
  .use(bodyParser.json())
  .use(bodyParser.urlencoded({ extended: true }))
  // Configure feathers-authentication
  .configure(auth({ secret: 'super secret' }))
  .configure(jwt())
  .use('/users', memory())
  .use(errorHandler());

app.listen(3030);

console.log('Feathers app started on 127.0.0.1:3030');