Why is req.somevariable and res.locals not working with if conditions?

We have a route & a middleware like this:

When we do them like this:

//middleware
router.use((req, res, next) => {

    // check header or url parameters or post parameters for token
    let token = req.body.token || req.query.token || req.headers['x-access-token'],


        // verifies secret and checks exp
        jwt.verify(token, config.secret, (err, decoded) => {
            if (err) {
                return res.json({
                    success: false,
                    message: 'Failed to authenticate token.'
                });
            } else {
                // if everything is good, save to request for use in other routes
                res.locals.test = "test";
                req.somevariable = "variable1";

                console.log("res.locals.test inside middleware ", JSON.stringify(res.locals.test));
                console.log("req.somevariable inside middleware ", JSON.stringify(req.somevariable));

                next();

            }
        });

    next();
});

//TestRoute
router.get('/TestRoute', (req, res) => {

    console.log("res.locals.test outside middleware ", JSON.stringify(res.locals.test));
    console.log("req.somevariable outside middleware ", JSON.stringify(req.somevariable));

});

The values of req.somevariable and res.locals.test are undefined outside middleware

When we do them like this:

//middleware
router.use((req, res, next) => {

    res.locals.test = "test";
    req.somevariable = "variable1";

    console.log("res.locals.test inside middleware ", JSON.stringify(res.locals.test));
    console.log("req.somevariable inside middleware ", JSON.stringify(req.somevariable));

    next();

});

//TestRoute
router.get('/TestRoute', (req, res) => {

    console.log("res.locals.test outside middleware ", JSON.stringify(res.locals.test));
    console.log("req.somevariable outside middleware ", JSON.stringify(req.somevariable));


});

The values of req.somevariable and res.locals.test are available outside middleware.

What is the problem here?

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