Authentication in Next.js Using NextAuth (Full Implementation)

// app/api/auth/[...nextauth]/route.ts
import NextAuth from "next-auth"
import GoogleProvider from "next-auth/providers/google"

const handler = NextAuth({
  providers: [
    GoogleProvider({
      clientId: process.env.GOOGLE_CLIENT_ID,
      clientSecret: process.env.GOOGLE_CLIENT_SECRET,
    }),
  ],
})

export { handler as GET, handler as POST }