Checkers ✅

Checkers are functions that verify authentication state in your Next.js application. They are returned by the createAuthLayer function and can be used in both server and client components.

Available Checkers 🎯

isAuth

Check if a user is authenticated:

const isAuthenticated = await isAuth()

isGuest

Check if a user is a guest (not authenticated):

const isGuestUser = await isGuest()

isUser

Check if a user is logged in:

const isLoggedIn = await isUser()

isAdmin

Check if a user is an admin:

const isAdminUser = await isAdmin()

isRole

Check if a user has a specific role:

const hasRole = await isRole({ role: 'editor' })

Usage Examples 📝

Server Components

// app/protected/page.tsx
import { isAdmin } from '@/lib/auth'

export default async function ProtectedPage() {
  const isAdminUser = await isAdmin()

  if (!isAdminUser) {
    return <div>Access denied</div>
  }

  return <div>Admin content</div>
}

API Routes

// pages/api/protected.ts
import { isAuth } from '@/lib/auth'

export default async function handler(req, res) {
  const isAuthenticated = await isAuth()

  if (!isAuthenticated) {
    return res.status(401).json({ error: 'Unauthorized' })
  }

  return res.status(200).json({ data: 'Protected data' })
}

Client Components

// components/ProtectedComponent.tsx
'use client'

import { useEffect, useState } from 'react'
import { isAuth } from '@/lib/auth'

export default function ProtectedComponent() {
  const [isAuthenticated, setIsAuthenticated] = useState(false)

  useEffect(() => {
    const checkAuth = async () => {
      const auth = await isAuth()
      setIsAuthenticated(auth)
    }
    checkAuth()
  }, [])

  if (!isAuthenticated) {
    return <div>Please log in</div>
  }

  return <div>Protected content</div>
}

Best Practices 📚

Use checkers for conditional rendering
Cache authentication state when possible
Handle loading states appropriately
Consider using guards for route protection
Use appropriate error handling

Checkers