json-server.js

const jsonServer = require('json-server');
const server = jsonServer.create();
const router = jsonServer.router('db.json');
const middlewares = jsonServer.defaults();
const bodyParser = require('body-parser');

const jwtToken = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJuYW1lIjoiU2l0ZVBvaW50IFJ' +
'lYWRlciJ9.sS4aPcmnYfm3PQlTtH14az9CGjWkjnsDyG_1ats4yYg';

// Use default middlewares (CORS, static, etc)
server.use(middlewares);

// Make sure JSON bodies are parsed correctly
server.use(bodyParser.json());

// Handle sign-in requests
server.post('/sign-in', (req, res) => {
	const username = req.body.username;
	const password = req.body.password;
	if(username === 'WitFlash' && password === 'admin') {
		res.json({
			name: 'My Todos App',
			token: jwtToken
		});
	}
	res.send(422, 'Invalid username and/or password');
});

// Protect other routes
server.use((req, res, next) => {
	if (isAuthorized(req)) {
		console.log('Access granted');
		next();
	} else {
		console.log('Access denied, invalid Token');
		res.sendStatus(401);
	}
});

// API routes
server.use(router);

// Start server
server.listen(3000, () => {
	console.log('JSON Server is running');
});

// Check whether request is allowed
function isAuthorized(req) {
	let bearer = req.get('Authorization');
	if (bearer === 'Bearer ' + jwtToken) {
		return true;
	}
	return false;
}