My code:

module.exports = async (req, res, next) => {

    const redirectURL = ((req.originalUrl.includes("login") || req.originalUrl === "/") ? "/selector" : req.originalUrl);
    
    if(req.session.user){
        return next();
    } else {
        const state = Math.random().toString(36).substring(5);
        req.client.states[state] = redirectURL;
        return res.redirect(`/api/login?state=${state}`);
    }
};

Give me this error:

Cannot set properties of undefined (setting 'yhgrz0jg')

Can anyone help me I've tried everything and I can't solve it?