How can i return User of different structure from authorize?

[typedashutosh]

In [...nextauth].ts, I've used credentials for signing in a client. after signing in, the authorize method should return a User object with id email and image .

But I want to return a custom UserObject with _id, firstname, lastname and username as parameters.

As soon as I does this, typescript start complaining this -->
Type 'Promise<UserObject | null>' is not assignable to type 'Promise<User | null>'.

The only way I could think of accomplishing this is by making changes in node_modules which doesn't seem to be good idea.

I also couldn't find any documentation or examples doing this, if found, weren't helpful or hard to understand.

dependencies: {
    "@types/next-auth": "^3.7.4",
    "next-auth": "^3.11.2",
    "typescript": "^4.2.3"
}

[rbatistajs]

I solved it by adding types.d.ts in my project.

extends interface "User" the of module "next-auth"

import 'next-auth'

declare module 'next-auth' {
  export interface User {
    _id?: string
    firstname?: string
    lastname?: string
    username?: string
  }
}

example extends other interface

/* eslint @typescript-eslint/no-empty-interface: "off" */
import 'next-auth'
import { UserObject } from './my-code/user'

declare module 'next-auth' {
  export interface User extends UserObject  {}
}

=============

Would be cool to do something like this in next-auth :/

[balazsorban44]

Working on it! :) #1649 has started this process, and I had the same idea at DefinitelyTyped/DefinitelyTyped#51926

[typedashutosh]

This method of explicitly defining types in separate file does work! Also I'd to include this:

declare module 'next-auth/jwt' {
  export interface JWT extends Record<string, unknown> {
    _id: string
    firstname: string
    lastname: string
    username: string
  }

so that i could return correct session to client with useSession().
Still, I'm getting these useless properties:

In your example, its also present there.

Question:
Is there a way to override default User and JWT types declared in @types/next-auth?

[balazsorban44]

I believe currently there is not. But I did consider type augmentation like you did here, and it would work even better than generics, especially for jwt and session.

cc @lluia please remind me of this next time we discuss this topic. 😊

[typedashutosh]

I've an Idea!
Can we have a user constructor, where we can specify user object, just like mongoose schema.
Example of mongoose schema:

const UserSchema = new Schema<IUser>(
  {
    firstname: { type: String, required: [true, 'Firstname is required'] },
    lastname: String,
    username: {
      type: String,
      unique: true,
      required: [true, 'Please provide a username']
    },
    password: { type: String, required: [true, 'Please provide a Password'] },
    blogs: { type: Array, required: false }
  }
)

We can have limited options for keys in user object like required.

What you say?

[balazsorban44]

will be addressing this through https://next-auth-git-feat-deduplicate-types-nextauthjs.vercel.app/getting-started/typescript
you will be able to augment User

This will soon be built-in you an follow #1690