How can I handle common checks across different endpoints in an Express application?

const express = require("express");

/**
 * Custom middleware to check that a request is authorized.
 *
 * The API would need to provide an endpoint e.g. `/authenticate`
 * which clients can use to authenticate themselves and receive
 * a JSON Web Token. They would then send this in the `Authorization`
 * header of subsequent requests to the API and this middleware
 * would verify that it is valid.
 *
 * @param {Object} request - Express request object 
 * @param {Object} response - Express response object
 * @param {Function} next - Express next function
 */
function verifyJsonWebTokenMiddleware (request, response, next) {
	const authorizationHeader = request.get('authorization');
	const jsonWebTokenIsValid = verifyJsonWebToken(authorizationHeader);

	if (jsonWebTokenIsValid) {
		/**
		 * The JSON Web Token is valid so we call the `next()`
		 * function to tell Express to run the next middleware.
		 * In this example it's whichever function has been
		 * defined as the route handler.
		 */
		return next();
	}
	
	/**
	 * The JSON Web Token is invalid so we're sending an
	 * error response to the client, and Express won't run
	 * any other middleware because we're not calling the
	 * `next()` function.
	 * 
	 * HTTP status is 401 Unauthorized (https://httpstatuses.com/401).
	 */
	return response.status(401).json({
		error: 'unauthorized',
		message: 'Invalid JSON Web Token. Request unauthorized.'
	});
}

/**
 * This function would contain code which verifies the
 * JSON Web Token that has been passed in the `Authorization`
 * header and would return true if it is valid, rather than
 * always returning false.
 */
function verifyJsonWebToken(authorizationHeader) {
	return false;
}

/**
 * Express configuration and routes
 */

const PORT = 3000;
const app = express();

/**
 * No other middleware will be run for this route.
 *
 * This would be the endpoint which authenticates a client
 * agaist a database and responds with a JSON Web Token.
 */
app.post('/authenticate', (request, response) => {
	response.json({ token: 'json-web-token' });
});

/**
 * Tell Express that we want every route which we define
 * after this to run this middleware function first.
 */
app.use(verifyJsonWebTokenMiddleware);

app.get('/user/:id', (request, response) => {
	response.json({ name: 'Some Person' });
});

app.put('/user/:id', (request, response) => {
	response.status(202).json({ status: 'updated' });
});

app.listen(PORT, () => console.log(`Example app listening at http://localhost:${PORT}`));