callbacks: {

    jwt: async (token, user, account, profile, isNewUser) => {

        //  "user" parameter is the object received from "authorize"

        //  "token" is being send below to "session" callback...

        //  ...so we set "user" param of "token" to object from "authorize"...

        //  ...and return it...

        user && (token.user = user);

        return Promise.resolve(token)   // ...here

    },

    session: async (session, user, sessionToken) => {

        //  "session" is current session object

        //  below we set "user" param of "session" to value received from "jwt" callback

        session.user = user.user;

        return Promise.resolve(session)

    }

}

​

// pages/api/auth/[...nextauth].ts

​

export default async function auth(req: NextApiRequest, res: NextApiResponse) {•

    return await NextAuth(req, res, {•

        providers: [ ... ],•

        session: {•

            strategy: "jwt",•

        },•

        cookies: cookies,•

        callbacks: { ... },•

    });•

}