Extending the Session in next-auth@^5.0.0-beta.25 is not working.

[xgbnl]

Environment

 System:
    OS: Linux 5.15 Ubuntu 24.04.2 LTS 24.04.2 LTS (Noble Numbat)
    CPU: (16) x64 13th Gen Intel(R) Core(TM) i5-13500H
    Memory: 6.25 GB / 7.58 GB
    Container: Yes
    Shell: 5.2.21 - /bin/bash
  Binaries:
    Node: 22.12.0 - /usr/local/lib/nodejs/node-v22.12.0-linux-x64/bin/node
    npm: 11.1.0 - /usr/local/lib/nodejs/node-v22.12.0-linux-x64/bin/npm
  npmPackages:
    @auth/prisma-adapter: ^2.7.4 => 2.7.4
    next: ^15.2.0 => 15.2.0
    next-auth: ^5.0.0-beta.24 => 5.0.0-beta.25
    react: 18.3.1 => 18.3.1

Reproduction URL

https://github.com/xgbnl/vuexy-kit-template

Describe the issue

I’m using next-auth@^5.0.0-beta.25, and I’m trying to extend the Session object according to the official documentation, but it doesn’t seem to be working as expected.

How to reproduce

1. I followed the next-auth v5 documentation (https://authjs.dev/getting-started/typescript?framework=next-js) to create a next-auth.d.ts file

next-auth.d.ts

import NextAuth, { type DefaultSession } from 'next-auth'

declare module 'next-auth' {
  /**
   * Returned by `auth`, `useSession`, `getSession` and received as a prop on the `SessionProvider` React Context
   */
  interface Session {
    user: {
      username: string
      avatar: string
    } & DefaultSession['user']
  }
}

2. I wrote the necessary code inside it and added the file to the include array in my tsconfig.json

  "include": [
    "next.config.ts",
    "tailwind.config.ts",
    "next-env.d.ts",
    "**/*.ts",
    "**/*.tsx",
    ".next/types/**/*.ts",
    "next-auth.d.ts"
  ],

3. However, the session object within the callback function is not returning the custom fields I defined as expected

  callbacks: {
    /*
     * While using `jwt` as a strategy, `jwt()` callback will be called before
     * the `session()` callback. So we have to add custom parameters in `token`
     * via `jwt()` callback to make them accessible in the `session()` callback
     */
    async jwt({ token, user }) {
      if (user) {
        /*
         * For adding custom parameters to user in session, we first need to add those parameters
         * in token which then will be available in the `session()` callback
         */
        token.name = user.name
      }

      return token
    },
    async session({ session, token, user }) {
      console.log('Custom Session',session)
      if (session.user) {
        // ** Add custom params to user in session which are added in `jwt()` callback via `token` parameter
        session.user.name = token.name
      }

      return session
    }
  }

4. Print Result

Custom Session {
  user: { name: undefined, email: undefined, image: undefined },
  expires: '2025-03-29T08:14:48.518Z'
}

Expected behavior

I’ve been working on this for a whole day without any success. I need your help.

[r-bromfield]

@xgbnl you need to update the jwt submodule as well

see example below

// The `JWT` interface can be found in the `next-auth/jwt` submodule
import { JWT } from "next-auth/jwt"
 
declare module "next-auth/jwt" {
  /** Returned by the `jwt` callback and `auth`, when using JWT sessions */
  interface JWT {
    /** OpenID ID Token */
    idToken?: string
   
  }
}

[xgbnl]

@xgbnl you need to update the jwt submodule as well

see example below

// The `JWT` interface can be found in the `next-auth/jwt` submodule
import { JWT } from "next-auth/jwt"
 
declare module "next-auth/jwt" {
  /** Returned by the `jwt` callback and `auth`, when using JWT sessions */
  interface JWT {
    /** OpenID ID Token */
    idToken?: string
   
  }
}

Thank you, I have resolved this issue, and it helps me get the IDE to suggest the object’s properties. I encountered a new problem where using throw new Error('error content') in the authorize() method of version beta25 seems to not be caught when using the signIn() method in the Login.tsx component. Do you have any good solutions for this?