'use server';

import { z } from 'zod';
import { sql } from '@vercel/postgres';
import { revalidatePath } from 'next/cache';
import { redirect } from 'next/navigation';
import { signIn } from '@/auth';
import { AuthError } from 'next-auth';

// Define the form schema using Zod for validation
const FormSchema = z.object({
  // ...
});

export async function createInvoice(formData: FormData) {
  //  ...
}

export async function updateInvoice(id: string, formData: FormData) {
  // ...
}

export async function deleteInvoice(id: string) {
  // ...
}

export async function authenticate(
  prevState: string | undefined,
  formData: FormData,
) {
  try {
    await signIn('credentials', formData);
  } catch (error) {
    if (error instanceof AuthError) {
      switch (error.type) {
        case 'CredentialsSignin':
          return 'Invalid credentials.';
        default:
          return 'Something went wrong.';
      }
    }
    throw error;
  }
}

Modify login form

Within the login-form.tsx component, leverage React's useFormState to invoke the server action.

app/ui/login-form.ts

'use client';

import { poppins } from '@/app/ui/fonts';
import {
  UserIcon,
  KeyIcon,
  ExclamationCircleIcon,
} from '@heroicons/react/24/outline';
import { ArrowRightIcon } from '@heroicons/react/20/solid';
import { Button } from './button';
import { useFormState } from 'react-dom';
import { authenticate } from '@/app/lib/actions';

export default function LoginForm() {
  const [_, dispatch] = useFormState(authenticate, undefined);

  return (
    <form action={dispatch} className="space-y-3">
      <div className="flex-1 rounded-lg bg-neutral-900 px-6 pb-4 pt-8">
        {/* ... */}
      </div>
    </form>
  );
}

// ...

In Practice

Everything was clear?

Section 7. Chapter 7

Course Content

Next.js 14

1. Introduction

Welcome Project Overview Course Prerequisites How the Course Works

2. Basic Concepts

Project Set Up Project File-Folder Strcture Styling Approaches Adding the Global CSS File Tailwind Styling CSS Modules Conditionally Applying Styles Custom Google Fonts Challenge: Adding Custom Google Font Images

3. Pages and Layouts

How Routing Works Challenge: Creating Page Creating a Common Layout Navigation Optimization Creating Active Links

4. Deployment and Database

Accounts Set Up Project Deployment Project Database Data Population

5. Working with Data

How to Fetch Data Working with the Dashboard Page Practice and Challenge: Retrieving Data Dynamic vs Static Rendering Loaders Specific Parts Loaders Challenge: Skeleton Loader Grouping Components for Loaders

6. Advanced Features

Invoices Page Search Functionality Pagination Server Actions Creating Item Updating Item Deleting Item Challenge: Form Validation

7. Authentication

Understanding Authentication Login Route NextAuth.js Authentication Configuration & Route Protection Password Hashing & Credentials Sign-in Functionality Connecting UI & Functionality Logout Functionality What's Next?

Next.js 14

Connecting UI & Functionality

Let's ensure that the login functionality is working correctly.

Back to the Project

1. Create the authenticate action

In the actions.ts file, establish a new action named authenticate. This action should incorporate the signIn function from auth.ts:

app/lib/actions.ts