example of ExpressJS endpoint logging an http error

users_routes.js

    app.post('/user/defaultLanguage', (req, res) => {
        const defaultLanguage = req.body.defaultLanguage;
        const userEmail = req.user.email;
        userLogic.updateUserDefaultLang(userEmail, defaultLanguage)
            .then(() => {
                res.end();
            })
            .catch((err) => {
                utils.logHttpRequestError(res.req, err);
                res.status(500).end();
            });
    })