Install NextAuth

yarn add next-auth

npm install next-auth

Version

    "next": "14.1.4",
    "next-auth": "^4.24.7"

Implementation

1. Let's start with Providers, For Google Login We need Google Provider (https://next-auth.js.org/providers/google)

    import GoogleProvider from "next-auth/providers/google";
    ...
    providers: [
      GoogleProvider({
        clientId: process.env.GOOGLE_CLIENT_ID,
        clientSecret: process.env.GOOGLE_CLIENT_SECRET
      })
    ]
    ...
   

2. Now, How can we get our clientID anf clientSecrect?

   • Go to Google Cloud Console - console.developers.google.com/apis/credenti..

   • Create a New Project

     

   • Select Create crendentials and add a OAuth client ID

     

   • The "Authorized redirect URIs" used when creating the credentials must include your full domain and end in the callback path. For example;

     • For production: https://{YOUR_DOMAIN}/api/auth/callback/google

     • For development: http://localhost:3000/api/auth/callback/google

       

   • Form here you can access your ClientID and Client Secret

   • Put them is you .env

3. Now you can separate out your Auth Options in authOptions.ts file

    //authOptions.ts
    import clientPromise from "@/lib/mongoClient";
    import {AuthOptions} from "next-auth";
    import GoogleProvider from "next-auth/providers/google";
   
    export const authOptions:AuthOptions = {
      secret: process.env.AUTH_SECRET,
      providers: [
        GoogleProvider({
          clientId: process.env.GOOGLE_CLIENT_ID as string,
          clientSecret: process.env.GOOGLE_CLIENT_SECRET as string,
        }),
      ],
    };
   

4. Now you need Adapter to store your users and sessions

   4. • Here we are using MongoDB to store out Users.(https://next-auth.js.org/adapters)

        • Add mongodb adapter

           yarn add @auth/mongodb-adapter mongodb
          
           //or
          
           npm install @auth/mongodb-adapter mongodb
          

        • Setup:

          1. Add MongoClient :

              //mongoClient.ts
              import { MongoClient } from "mongodb";
             
              if (!process.env.MONGODB_URI) {
                throw new Error("Please add your Mongo URI to .env.local");
              }
             
              const uri: string = process.env.MONGODB_URI;
              let client: MongoClient;
              let clientPromise: Promise<MongoClient>;
             
              if (process.env.NODE_ENV === "development") {
                // In development mode, use a global variable so that the value
                // is preserved across module reloads caused by HMR (Hot Module Replacement).
             
                let globalWithMongoClientPromise = global as typeof globalThis & {
                  _mongoClientPromise: Promise<MongoClient>;
                };
             
                if (!globalWithMongoClientPromise._mongoClientPromise) {
                  client = new MongoClient(uri);
                  globalWithMongoClientPromise._mongoClientPromise = client.connect();
                }
             
                clientPromise = globalWithMongoClientPromise._mongoClientPromise;
              } else {
                // In production mode, it's best to not use a global variable.
                client = new MongoClient(uri);
                clientPromise = client.connect();
              }
             
              // Export a module-scoped MongoClient promise. By doing this in a
              // separate module, the client can be shared across functions.
              export default clientPromise;
             

             2. Config Auth.js : use MongoDBAdapter (in Our case authOptions.js)

                  adapter: MongoDBAdapter(clientPromise)
                

                Finally Auth.js File -

                 //authOptions.ts
                 import clientPromise from "@/lib/mongoClient";
                 import {MongoDBAdapter} from "@auth/mongodb-adapter";
                 import {AuthOptions} from "next-auth";
                 import GoogleProvider from "next-auth/providers/google";
                
                 export const authOptions:AuthOptions = {
                   secret: process.env.AUTH_SECRET,
                   providers: [
                     GoogleProvider({
                       clientId: process.env.GOOGLE_CLIENT_ID as string,
                       clientSecret: process.env.GOOGLE_CLIENT_SECRET as string,
                     }),
                   ],
                     // @ts-ignore
                     adapter: MongoDBAdapter(clientPromise),
                 };
                

   5. Now Create a userClient.ts using authOptions

       //userClient.ts
       import {authOptions} from "@/lib/authOptions";
       import {getServerSession} from "next-auth";
      
       export async function getUserEmail(): Promise<string> {
         const session = await getServerSession(authOptions);
         return session?.user?.email || '';
       }
      

   6. Now Create a API route for login in : api/auth/[...nextauth]

       //route.ts
       import NextAuth from "next-auth"
       import { authOptions } from "@/lib/authOptions";
      
       const handler = NextAuth(authOptions);
      
       export { handler as GET, handler as POST }
      

   7. Let's Create a Login Page :

      Just use the signIn('google') and BOOMMMM!!

       'use client';
       import { signIn } from "next-auth/react";
      
       export default function LoginButton() {
        return (
         <button onClick={() => signIn('google')}
          className="bg-gray-300 py-2 px-4 ml-2 rounded-md">
          Login
         </button>
        );
       }
      

   8. Now to handle Logout:

      We have magical singOut()

       'use client';
       import {FontAwesomeIcon} from "@fortawesome/react-fontawesome";
       import { signOut } from "next-auth/react";
       import {faArrowRightFromBracket} from "@fortawesome/free-solid-svg-icons";
      
       export default function LogoutButton() {
        return (
         <button onClick={() => signOut()}
          className="bg-gray-300 py-2 px-4 ml-2 rounded-md inline-flex gap-2 items-center">
          Logout
          <FontAwesomeIcon icon={faArrowRightFromBracket} />
         </button>
        );
       }