Next Auth V5 Augment Typescript User Interface doesnt work

[cexra]

What is the improvement or update you wish to see?

next auth js provides documentation that does not work to augment the User interface in the @auth/core module.

Is there any context that might help us understand?

from the existing documentation we can augment the User interface like the method below

next-auth.d.ts

import { JWT } from '@auth/core/jwt'
import { type DefaultSession } from 'next-auth'

declare module '@auth/core' {
  interface Session {
    user: {
      id: string
      identifier: string
      role: 'USER' | 'ADMIN'
      name: string
    } & DefaultSession['user']
  }

  interface User {
    id: string
    identifier: string
    name: string
    role: 'USER' | 'ADMIN'
  }
}

declare module '@auth/core/jwt' {
  interface JWT {
    identifier: string
    name: string
    role: 'USER' | 'ADMIN'
  }
}

augment Session interface and JWT interface it works. but augment User interface does not work. my purpose of augmenting the User interface is to persist the role attribute on the User object, so that I can store it on the Session object.

auth.config.ts

import type { NextAuthConfig } from 'next-auth'

export const authConfig = {
  callbacks: {
    jwt({ token, user }) {
      if (user) token.role = user.role // Property 'role' does not exist on type 'User | AdapterUser'. Property 'role' does not exist on type 'User'.ts(2339)
      return token
    },

    session({ session, token }) {
      session.user.role = token.role
      return session
    },
  },
} satisfies NextAuthConfig

Does the docs page already exist? Please link to it.

https://authjs.dev/getting-started/typescript?frameworks=next

[judewang]

@cexra Try using @auth/core/types rather than @auth/core, that worked for me.

[cexra]

yes the solution works but only partially, the solution solves the problem on jwt and session callback. but why user.name is still a string | null | undefined when I think user.name should be a string only. can anyone help me how to augment this type

[Constantiner]

import "next-auth";

declare module "next-auth" {
	interface User {
		role: "SUPER" | "USER";
	}

	interface Session {
		user?: User;
	}
}

declare module "@auth/core/jwt" {
	interface JWT {
		role: "SUPER" | "USER";
	}
}

This works for me.

[KrisTemmerman]

I tried both ways, and i run into the same issue:
Property 'id' does not exist on type '{ name?: string | null | undefined; email?: string | null | undefined; image?: string | null | undefined; }'.

import NextAuth from "next-auth";
import Discord from "next-auth/providers/discord";
import type { NextAuthConfig } from "next-auth";
import { DrizzleAdapter } from "@auth/drizzle-adapter";
import { db } from "@/app/db";
import { pgTable } from "./db/schema";
import { env } from "@/env.mjs";

enum UserRole {
  Admin = "admin",
  User = "user",
  Free = "free",
}

declare module "@auth/core/types" {
  interface Session {
    user: {
      id: string;
      // ...other properties
      role: UserRole;
    } & DefaultSession["user"];
  }

  interface User {
    // ...other properties

    role: UserRole;
  }
}

export const config = {
  theme: {
    logo: "https://next-auth.js.org/img/logo/logo-sm.png",
  },
  providers: [
    Discord({
      clientId: env.DISCORD_CLIENT_ID,
      clientSecret: env.DISCORD_CLIENT_SECRET,
    }),
  ],
  adapter: DrizzleAdapter(db, pgTable),

  callbacks: {
    session: ({ session, user }) => ({
      ...session,
      user: {
        ...session.user,
        id: user.id,
        role:session.user?.role
      },
    }),
  },
} satisfies NextAuthConfig;

export const { handlers, auth } = NextAuth(config);

[Constantiner]

Have you tried to put your augmented types into a separate .d.ts file?

[KrisTemmerman]

I needed to update my package to next-auth": "5.0.0-beta.4 and drizzle-adapter:"^0.3.9", and could just run it inline.
Thanks all for confirming it was me and not NextAuth.

import NextAuth from "next-auth";
import Discord from "next-auth/providers/discord";
import type { NextAuthConfig } from "next-auth";
import { DrizzleAdapter } from "@auth/drizzle-adapter";
import { db } from "@/app/db";
import { pgTable } from "./db/schema";
import { env } from "@/env.mjs";

enum UserRole {
  Admin = "admin",
  User = "user",
  Free = "free",
}

declare module "@auth/core/types" {
  interface Session {
    user: {
      id: string;
      // ...other properties
      role: UserRole;
    } 
  }

  interface User {
    // ...other properties

    role: UserRole;
  }
}

export const config = {
  theme: {
    logo: "https://next-auth.js.org/img/logo/logo-sm.png",
  },
  providers: [
    Discord({
      clientId: env.DISCORD_CLIENT_ID,
      clientSecret: env.DISCORD_CLIENT_SECRET,
    }),
  ],
  adapter: DrizzleAdapter(db, pgTable),

  callbacks: {
    session: ({ session, user }) => ({
      ...session,
      user: {
        ...session.user,
        id: user.id,
        role: session.user?.role,
      },
    }),
  },
} satisfies NextAuthConfig;

export const { handlers, auth } = NextAuth(config);

[andreluis-oliveira]

@cexra Try using @auth/core/types rather than @auth/core, that worked for me.

thanks bro

[ypanagidis]

I gave this a go today and no luck still unfortunately. How come this works for you guys when this is still open? #8561

[chungweileong94]

So I spend quite some time debugging this, as both @auth/core & @auth/core/types doesn't work for me, and I don't think adding the /types is really necessary.

I managed to solve it by making the user optional, which make sense as the user can be undefined when user is not login.

declare module "next-auth" {
  interface Session {
    user?: {
      id: string;
      // ...other properties
      role: UserRole;
    } 
  }
}

Notice that it also works with next-auth in my case, so I believe it should also works with @auth/core & @auth/core/types.

[rvndev]

I've tested various releases of next-auth@beta, however, I am still unable to overwrite the default values in the User interface. I saved the following into next-auth.d.ts, however, I am still getting an error when I try to assign a Number to id in authorize().

declare module "next-auth" {
  interface User {
    id: number;
  }

  interface Session {
    user?: User;
  }
}

declare module "@auth/core" {
  interface User {
    id: number;
  }
}

declare module "@auth/core/types" {
  interface User {
    id: number;
  }
}

[ndom91]

@rvndev did you include your next-auth.d.ts in your tsconfig.json types?

I've added this snippet in my auth.config.ts and it seemed to work:

declare module "next-auth" {
  interface Session {
    user: {
      address: string
    } & User
  }

  interface User {
    foo?: string
  }
}

Check this out for more details: https://authjs.dev/getting-started/typescript