I tried the following, but I couldn't get the addition from the client and server side environment.

The callbacks function allows you to add to a session, but I just want to add user information and designate it as a default session.

// @types/next-auth.d.ts

import 'next-auth';

declare module 'next-auth' {
  interface User {
    id: string;
    name?: string | null;
    email?: string | null;
    image?: string | null;
    address?: string | null;
  }
}

// [...nextauth].ts

import NextAuth from 'next-auth';
import CredentialsProvider from 'next-auth/providers/credentials';
import { buildFeedbackPath, extractFeedback } from '../../../lib/user';
import type { NextAuthOptions } from 'next-auth';

export const authOptions: NextAuthOptions = {
  providers: [
    CredentialsProvider({
      name: 'Credentials',
      async authorize(credentials, req) {
        // Add logic here to look up the user from the credentials supplied
        const filePath = buildFeedbackPath();
        const userData = extractFeedback(filePath);

        const user = userData.find((userinfo) => userinfo.email === credentials?.email);
        if (!user) {
          throw new Error('No user found!');
        }
        return { email: user.email, image: '11233', address: 'testr' };
      },
    }),
  ],
  callbacks: {
    async session({ session, token, user }) {
      // console.log('session!!', session.user);
      return session;
    },
  },
};

export default NextAuth(authOptions);

serverside

export const getServerSideProps: GetServerSideProps = async (context) => {
  const session = await unstable_getServerSession(context.req, context.res, authOptions);

  console.log(session);

  if (!session) {
    return {
      redirect: {
        destination: '/login',
        permanent: false,
      },
    };
  }

  return {
    props: {},
  };
};

result

Why can't I expand the address?

CodePudding user response：

we add more properties in session callback:

 async session({ session, token, user }) {
    console.log('userin session', session);
    session.user.address = 'testr';
    return session;
},

Because if you visit node_modules/next-auth/core/types.d.ts/Session this is the DefaultUser

export interface DefaultUser {
    id: string;
    name?: string | null;
    email?: string | null;
    image?: string | null;
}

this is why, in your console.log, "name" property exists but its value does not exist, it returns undefined, but "image" exisits in DefaultUser, that is why you could image: '11233' but not "address" because "address" does not exist in DefaultUser properties.