问如何从节点js向React js呈现带有响应数据的页面？

EN

router.get(
    '/auth/google/callback',
    passportGoogle.authenticate('google', {
        failureRedirect: '/',
    }),
    (req, res) => {
        const nameFirst = req.user.profile._json.displayName;
        const picture = req.user.profile._json.image.url;
        const email = req.user.profile.emails[0].value;
        const id = req.user.profile.id;
        const user = new User({
            user_token: id,
            name: nameFirst,
            email: email,
            picture: picture,
            provider: 'Google',
            dateSent: Date.now(),
        });
    User.findOne({ email: email }, (err, docs) => {
        if (docs != null) {
                            // already exist
                    } else {
                            // send data  `user`  with routing [routing to /signupnext,]
                    }
    });