fix(ts): TS Module Augmentation (#5556)

* fix: TS Module Augmentation

* match type to AdapterUser

* refactor authorize callback

* Apply suggestions from code review

* Apply suggestions from code review

* Apply suggestions from code review

Co-authored-by: Balázs Orbán <info@balazsorban.com>

Author: ThangHuuVu

apps/dev/types/nextauth.d.ts

@@ -0,0 +1,18 @@
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+import NextAuth from "next-auth"
+
+declare module "next-auth" {
+  /**
+   * Returned by `useSession`, `getSession` and received as a prop on the `SessionProvider` React Context
+   */
+  interface Session {
+    user: {
+      /** The user's postal address. */
+      address: string
+    } & User
+  }
+
+  interface User {
+    foo: string
+  }
+}

packages/next-auth/src/core/lib/email/getUserFromEmail.ts

@@ -1,19 +1,20 @@
+import type { AdapterUser } from "../../../adapters"
 import type { InternalOptions } from "../../types"
 
-export default async function getUserFromEmail({
+/**
+ * Query the database for a user by email address.
+ * If is an existing user return a user object (otherwise use placeholder).
+ */
+export default async function getAdapterUserFromEmail({
   email,
   adapter,
-  withId = false,
 }: {
   email: string
   adapter: InternalOptions<"email">["adapter"]
-  withId: boolean
-}) {
+}): Promise<AdapterUser> {
   const { getUserByEmail } = adapter
-  // If is an existing user return a user object (otherwise use placeholder)
-  return (email ? await getUserByEmail(email) : null) ?? withId
-    ? { id: email, email }
-    : {
-        email,
-      }
+  const adapterUser = email ? await getUserByEmail(email) : null
+  if (adapterUser) return adapterUser
+
+  return { id: email, email, emailVerified: null }
 }

packages/next-auth/src/core/routes/callback.ts

@@ -1,7 +1,7 @@
 import oAuthCallback from "../lib/oauth/callback"
 import callbackHandler from "../lib/callback-handler"
 import { hashToken } from "../lib/utils"
-import getUserFromEmail from "../lib/email/getUserFromEmail"
+import getAdapterUserFromEmail from "../lib/email/getUserFromEmail"
 
 import type { InternalOptions } from "../types"
 import type { RequestInternal, OutgoingResponse } from ".."
@@ -217,7 +217,7 @@ export default async function callback(params: {
         return { redirect: `${url}/error?error=Verification`, cookies }
       }
 
-      const profile = await getUserFromEmail({
+      const profile = await getAdapterUserFromEmail({
         email: identifier,
         // @ts-expect-error -- Verified in `assertConfig`. adapter: Adapter<true>
         adapter,
@@ -320,14 +320,14 @@ export default async function callback(params: {
   } else if (provider.type === "credentials" && method === "POST") {
     const credentials = body
 
-    let user: User
+    let user: User | null
     try {
-      user = (await provider.authorize(credentials, {
+      user = await provider.authorize(credentials, {
         query,
         body,
         headers,
         method,
-      })) as User
+      })
       if (!user) {
         return {
           status: 401,

packages/next-auth/src/core/routes/signin.ts

@@ -1,6 +1,6 @@
 import getAuthorizationUrl from "../lib/oauth/authorization-url"
 import emailSignin from "../lib/email/signin"
-import getUserFromEmail from "../lib/email/getUserFromEmail"
+import getAdapterUserFromEmail from "../lib/email/getUserFromEmail"
 import type { RequestInternal, OutgoingResponse } from ".."
 import type { InternalOptions } from "../types"
 import type { Account } from "../.."
@@ -55,11 +55,10 @@ export default async function signin(params: {
       return { redirect: `${url}/error?error=EmailSignin` }
     }
 
-    const user = await getUserFromEmail({
+    const user = await getAdapterUserFromEmail({
       email,
       // @ts-expect-error -- Verified in `assertConfig`. adapter: Adapter<true>
       adapter: options.adapter,
-      withId: true,
     })
 
     const account: Account = {

packages/next-auth/src/core/types.ts

@@ -265,7 +265,7 @@ export interface CallbacksOptions<P = Profile, A = Account> {
    * [Documentation](https://next-auth.js.org/configuration/callbacks#sign-in-callback)
    */
   signIn: (params: {
-    user: User | { email: string }
+    user: User | AdapterUser
     account: A | null
     /**
      * If OAuth provider is used, it contains the full
@@ -317,7 +317,7 @@ export interface CallbacksOptions<P = Profile, A = Account> {
    */
   session: (params: {
     session: Session
-    user: User
+    user: User | AdapterUser
     token: JWT
   }) => Awaitable<Session>
   /**
@@ -385,9 +385,9 @@ export interface EventCallbacks {
   createUser: (message: { user: User }) => Awaitable<void>
   updateUser: (message: { user: User }) => Awaitable<void>
   linkAccount: (message: {
-    user: User | AdapterUser | { email: string }
+    user: User | AdapterUser
     account: Account
-    profile: User | AdapterUser | { email: string }
+    profile: User | AdapterUser
   }) => Awaitable<void>
   /**
    * The message object will contain one of these depending on

packages/next-auth/src/providers/credentials.ts

@@ -17,7 +17,7 @@ export interface CredentialsConfig<
   authorize: (
     credentials: Record<keyof C, string> | undefined,
     req: Pick<RequestInternal, "body" | "query" | "headers" | "method">
-  ) => Awaitable<(Omit<User, "id"> | { id?: string }) | null>
+  ) => Awaitable<User | null>
 }
 
 export type CredentialsProvider = <C extends Record<string, CredentialInput>>(