Converting Figma Designs to Code with AI: A Practical Guide Using Looi Lightning and Loco AI

2025-03-02 14:20:45.520993

Introduction

This chapter provides a comprehensive guide on leveraging Artificial Intelligence (AI) to accelerate front-end development by converting Figma designs into production-ready code. We will explore the capabilities of Looi Lightning, a Figma plugin powered by Loco AI, to streamline the design-to-code workflow. This process will encompass not only code generation but also deployment, culminating in a fully functional web application.

We will be building a practical project: a homestay rental application named “Local Host,” similar to Airbnb. This application will feature property listings, map integration, and user authentication (sign-up and sign-in functionalities).

This chapter is designed for individuals with varying levels of coding experience. While some coding knowledge will be beneficial, especially for customization, we will guide you through each step, ensuring a clear and understandable learning experience.

Course Outline

This chapter will cover the following key stages:

Introduction to Figma: Understanding the fundamentals of Figma as a design tool.
Exploring the Design: Analyzing the provided Figma design file for the “Local Host” application.
Looi Lightning and Loco AI: Introducing the AI-powered plugin for design-to-code conversion.
Building the Application: Step-by-step guide on using Looi Lightning to generate code from the Figma design.
Setting up GitHub: Integrating the generated code with a GitHub repository for version control.
Database and Backend Creation: Establishing a database and building a backend to handle data and authentication.
Deployment: Deploying the application to make it accessible online.

Technology Stack

The “Local Host” application will be built using the following technologies:

Frontend: React - A JavaScript library for building user interfaces.
Backend: Node.js - A JavaScript runtime environment that executes JavaScript code server-side.
Database: MongoDB - A NoSQL database used for storing application data.
Deployment: Netlify - A platform for deploying and hosting web applications.

Figma: The Foundation for Design

Figma is a leading collaborative web design tool renowned for its user-friendly interface and real-time collaboration features. It empowers designers to create both User Interface (UI) and User Experience (UX) designs efficiently, often as teams working simultaneously. Figma offers a free tier, making it accessible for learning and project development.

Figma: A cloud-based design tool primarily used for creating user interfaces and user experiences. It is known for its collaborative features and accessibility through web browsers and desktop applications.

Accessing the Design File

To begin, you will need to access the Figma design file for the “Local Host” application.

Navigate to Figma Website: Go to figma.com.
Sign Up or Log In: Create a free account or log in if you already have one.
Open the Design File: Use the link provided in the transcript’s video description to access the “Local Host” Figma design file. Paste the link into your browser and press Enter.
Open in Figma: Once the design file loads, click “Open in Figma.” If you are logged in, it will open directly in your Figma workspace. If not, it will prompt you to log in or create an account.

Exploring the “Local Host” Design

The Figma file is organized into pages, which can be found under the “Getting Started” section in the left sidebar. Let’s explore the key pages:

Homepage: This page showcases the main interface for users to browse and filter holiday homes. It includes elements such as:
- Search filters (location, check-in/check-out dates, number of guests).
- Property listings displayed as cards.
Property Details Page: This page displays detailed information for a selected property, including:
- Large image gallery and thumbnail previews.
- Property title, location, rating, and review count.
- ”Like” functionality.
- Property description and amenities.
- Pricing information and booking options.
- Host information.
- Map integration based on coordinates.
- Weather information.
- User reviews.
- Similar stays recommendations.
Sign Up Page: This page provides a form for new users to create an account, requiring:
- Email address.
- Password and password confirmation fields.
- Option to sign up with Google, Facebook, or Apple.
Sign In Page: This page allows existing users to log in using:
- Email address.
- Password.

User Interface (UI) Design focuses on the visual elements and interactive aspects of a product, ensuring it is aesthetically pleasing and easy to use.

User Experience (UX) Design encompasses the overall experience a user has while interacting with a product or service, focusing on usability, accessibility, and user satisfaction.

User Interface (UI) Design: The process of designing the visual layout and interactive elements of a user interface. It focuses on aesthetics, branding, and making the interface easy and pleasant to use.

User Experience (UX) Design: The process of designing a product or service to provide a meaningful and relevant experience to users. It encompasses usability, accessibility, and overall user satisfaction throughout their interaction.

Feel free to navigate through the Figma file, explore different elements, and familiarize yourself with the design before proceeding to the code generation phase. Notice how elements are grouped and organized within frames and components.

Looi Lightning: AI-Powered Code Conversion

Looi Lightning is a Figma plugin that utilizes Loco AI to convert Figma designs into high-quality, production-ready frontend code automatically. Loco AI’s “large design models,” trained on vast datasets of designs and web applications, power this rapid conversion.

Plugin: A software component that adds specific features to an existing computer program. In the context of Figma, plugins extend its functionality, such as Looi Lightning for code generation.

Loco AI: The artificial intelligence engine behind Looi Lightning, specializing in design-to-code conversion. It leverages machine learning models trained on a large dataset of designs and web applications.

Signing Up for Loco AI and Installing the Figma Plugin

Sign Up for Loco AI:
- Go to loco.ai.
- Click on “Try for Free” to begin the sign-up process.
- Sign up using your Google account or another preferred method.
- Complete the onboarding questions, selecting options that align with your role (e.g., Founder, Full Stack Developer, Startup) and project goals.
- Choose Figma as your design tool and React as your desired framework.
Install the Figma Plugin:
- After signing up for Loco AI, you will be prompted to get the Figma plugin.
- Click on the provided link, which will take you to the Looi Lightning plugin page in the Figma Community.
- Click “Install” to add the plugin to your Figma account.
- Once installed, return to your Figma design file (“Local Host”).

Generating Code with Looi Lightning

Select Frames for Conversion: In Figma, navigate to the “Getting Started” page and select all the page frames you wish to convert to code (Homepage, Property Details Page, Sign Up Page, Sign In Page).
Run the Looi Lightning Plugin:
- In Figma, right-click anywhere on the canvas.
- Go to “Plugins” and select “Looi Lightning” (it might also appear under “Recent plugins”).
- The Looi Lightning plugin panel will appear.
Configure Project Settings:
- Click “Let’s Go” in the plugin panel.
- Name your project (e.g., “Localhost Website”).
- Select “Web App” as the project type.
- Choose “React” as the framework.
- Select “TypeScript” as the language (optional, can be changed later).
- Choose “CSS Modules” for styling (optional, can be changed later).
- Keep “Pixels” as units and “Pascal Case” for component naming (these can also be adjusted later).
- Select “Material UI” as the UI library for optimal preview and code conversion.
- Click “Create”.

Looi Lightning will now process your selected Figma frames and generate frontend code. This process involves several intelligent operations:

Responsive Design Generation: The AI automatically creates responsive layouts, adapting the design to different screen sizes (desktop, tablet, mobile).
Interactive Element Tagging: Interactive elements like inputs and buttons are intelligently identified and tagged, preparing them for functionality implementation.
Reusable Component Creation: The plugin identifies and generates reusable components, mirroring React’s component-based architecture, which promotes code maintainability and efficiency.
Human-Readable Class Names and Layer Names: Looi Lightning aims to generate code with clear and understandable class names and layer names, improving code readability for developers.

Front-end Code: The part of a web application that users directly interact with in their web browser. It is typically built using HTML, CSS, and JavaScript, and handles the user interface and user experience.

Production-ready Code: Code that is written and tested to be suitable for deployment in a live, operational environment. It is typically robust, efficient, and adheres to coding best practices.

Responsive Design: A web design approach that aims to make web pages render well on a variety of devices and screen sizes, from desktop monitors to mobile phones.

Reusable Components: Self-contained blocks of code that can be used multiple times throughout an application. In React, components are fundamental building blocks for creating user interfaces.

Class Names: Attributes in HTML elements used to apply CSS styles and JavaScript behaviors to specific elements or groups of elements. They are essential for styling and manipulating web page content.

Once the code generation is complete, Looi Lightning will display a preview of your generated application.

Reviewing and Customizing the Generated Code

Looi Lightning provides a preview of the generated code, allowing you to interact with the design and examine the code output.

Exploring Responsiveness and Interactivity

Responsiveness Preview: Use the screen size dropdown in the Looi Lightning preview to observe how the design adapts to different screen widths (e.g., desktop, tablet, mobile).
Interactive Elements: Test the interactivity of input fields and buttons in the preview. For instance, try selecting dates in the date input fields or interacting with dropdown menus.

Examining Code Quality and Structure

Code Readability: Review the generated code, paying attention to class names and component structure. Assess if the code is well-organized and easy to understand.
Component Breakdown: Observe how the design has been broken down into React components. Identify reusable components and their hierarchical structure.
Code Settings: Access the “Settings” within the Looi Lightning panel to view and modify project settings such as language (TypeScript/JavaScript), styling (CSS Modules/CSS), and naming conventions. Changes made here will be reflected in the generated code.

Reviewing and Editing AI Decisions

Looi Lightning offers a “Review Loco AI’s decisions” panel, allowing you to inspect and modify various aspects of the code generation process:

Responsiveness: If you are not satisfied with the responsiveness of a specific element, you can edit its CSS rules directly within the plugin. For example, you can adjust layout properties like flex or grid to fine-tune responsiveness for different screen sizes.
Tagging: Review how elements have been tagged (e.g., inputs, buttons). You can edit the properties of input fields, such as changing the input type from “text” to “password” to enable password masking and browser-based password management. You can also mark input fields as “required” to enforce form validation.
Layer Names: Review the automatically generated layer names and class names. If you prefer more descriptive names, you can edit them directly.
Code Components and Props: Examine the generated React components and their props (properties). You can review the props passed to each component and modify them as needed. You can also remove unnecessary props or add new ones.

CSS Variables: Custom properties defined in CSS that allow you to store and reuse values throughout your stylesheets. They enhance maintainability and theming capabilities.

CSS Modules: A system that locally scopes CSS class names by default. This prevents naming collisions and improves CSS encapsulation within components.

CSS Properties: Attributes in CSS that define the visual style of HTML elements, such as color, font-size, margin, and padding.

TypeScript: A superset of JavaScript that adds optional static typing. It helps catch errors during development and improves code maintainability, especially in larger projects.

JavaScript: A programming language primarily used for front-end web development to create interactive and dynamic web pages. It is executed in the user’s web browser.

React: A JavaScript library for building user interfaces. It emphasizes component-based architecture and efficient updates to the user interface.

Node.js: A JavaScript runtime environment that allows JavaScript code to be executed server-side. It is commonly used for building backends and APIs for web applications.

MongoDB: A NoSQL database that stores data in flexible, JSON-like documents. It is known for its scalability and ease of use in web applications.

Netlify: A platform for deploying and hosting web applications. It offers features like continuous deployment, serverless functions, and global CDN.

GitHub: A web-based platform for version control and collaboration using Git. It is widely used for managing source code and tracking changes in software development projects.

Repository: A storage location for software projects, typically managed by a version control system like Git. It contains all project files and their revision history.

By utilizing the review and editing features in Looi Lightning, you can refine the generated code to better align with your specific requirements and coding preferences. This iterative process of AI-assisted generation and human refinement is a key advantage of using tools like Looi Lightning.

Transitioning to Looi Builder: Expanding Development Capabilities

After reviewing and customizing the code in Figma, the next step is to sync your project to Looi Builder. Looi Builder is a web-based platform provided by Loco AI that offers a more comprehensive environment for further development, code modification, data integration, and deployment preparation.

Looi Builder: A web-based platform provided by Loco AI that extends the capabilities of Looi Lightning. It offers features for code modification, data binding, component management, and deployment preparation.

Syncing to Looi Builder

Ensure Frames are Selected: In Figma, make sure you have selected all the page frames you want to include in your Looi Builder project.
Click “Continue in Builder”: In the Looi Lightning plugin panel, click the “Continue in Builder” button.
Sync to Builder: Confirm that you want to sync the selected frames to Looi Builder.

Once synced, your project will be accessible within the Looi Builder platform.

Exploring Looi Builder Features

Looi Builder provides a range of features to enhance your development workflow:

Live Sharable Prototype: Looi Builder generates a live, interactive prototype of your application. This prototype is responsive and reflects the generated code. You can share this prototype with stakeholders for feedback and testing via a shareable link or email.
Auto Components and Props Management: Looi Builder allows you to manage and create components and props directly within the platform. You can create new components, modify existing ones, and define props to pass data between components. This feature integrates with component libraries like Storybook, facilitating component management in larger projects.

Prototype: An early sample, model, or release of a product built to test a concept or process. In web development, prototypes are often interactive mockups used to demonstrate functionality and gather feedback before full development.

Storybook: An open-source tool for developing UI components in isolation. It provides a sandbox environment to build, test, and document UI components independently from the main application.

Data Types: Classifications of data that specify the kind of value a variable can hold (e.g., string, number, boolean, array, object). Specifying data types helps ensure data integrity and can improve code readability and maintainability, especially in TypeScript.

Props (Properties): Inputs to React components. They are read-only values passed from parent components to child components, allowing data to flow down the component tree and customize component behavior and appearance.

Code Configuration: Looi Builder retains the code configuration settings you initially chose in Figma (language, styling, naming conventions). You can modify these settings within Looi Builder, and the changes will be reflected in the generated code.
Data Binding: Looi Builder enables data binding, allowing you to connect UI elements to data sources. You can bind UI elements to:
- State Variables: Manage component-level data using state variables.
- Components and Props: Bind data to component props for dynamic content rendering.
- Database Rendering: Configure data rendering from a database, especially useful for repeated components like lists or grids.

State Variables: Variables within a React component that hold data that can change over time. When a state variable changes, React re-renders the component to reflect the updated data in the user interface.

Data Binding: A technique that establishes a connection between data and UI elements. Changes in the data automatically update the UI elements, and vice-versa, simplifying data management and UI synchronization in applications.

Sync, Export, and Deploy Options: Looi Builder offers options to:
- Sync to GitHub: Integrate your project with a GitHub repository for version control and collaborative development.
- Export Code: Download the generated code for local development and customization in your preferred code editor.
- Deploy to Platforms: Deploy your application directly to platforms like Netlify or Vercel from within Looi Builder.

CI/CD Pipelines (Continuous Integration/Continuous Delivery Pipelines): Automated processes used in software development to build, test, and deploy code changes frequently and reliably. CI focuses on integrating code changes, while CD focuses on delivering those changes to production environments. While not explicitly detailed, Looi Builder’s sync and deploy capabilities are steps toward integrating with CI/CD workflows.

From Design to Development: Local Setup and Functionality

Having explored Looi Builder, the next step is to transition to a local development environment for more in-depth code customization and backend integration.

Syncing Code to GitHub

Connect to GitHub: In Looi Builder, navigate to the “Sync & Export & Deploy” settings. Connect your Looi Builder account to your GitHub account.
Create a New Repository: Choose to create a new GitHub repository for your project. Name the repository (e.g., “loco-host-app”).
Confirm and Sync: Confirm the repository name and branch, and initiate the sync process. Looi Builder will push the generated code to your new GitHub repository.

Cloning the Repository and Setting Up Locally

Clone the Repository: On your local machine, open your terminal or command prompt. Navigate to your desired project directory using the cd command. Clone the GitHub repository to your local machine using the git clone <repository-url> command, replacing <repository-url> with the URL of your GitHub repository.
Navigate to Project Directory: Use cd <repository-name> to enter the newly cloned project directory.
Install Dependencies: Run npm install (or yarn install) in the terminal to install all project dependencies listed in the package.json file. This step downloads and installs necessary libraries and packages, including React, Material UI, and other utilities.

Cloning: In Git, cloning refers to creating a local copy of a remote repository on your computer. This allows you to work on the codebase locally and synchronize changes with the remote repository.

Dependencies: External libraries or packages that a software project relies on to function correctly. They are typically managed by package managers like npm or yarn.

npm install: A command used in Node.js projects to install dependencies listed in the package.json file. npm (Node Package Manager) is a package manager for JavaScript.

Localhost: A hostname that refers to the current computer being used to access a network service. In web development, localhost:3000 typically refers to a web server running on your own machine, accessible through port 3000.

Start the Development Server: Run npm run start in the terminal. This command, as defined in your package.json scripts, usually starts a development server that hosts your React application. The application will typically be accessible in your web browser at http://localhost:3000.

Adding Basic Functionality: “Show More” Button

To demonstrate adding functionality to the generated code, let’s implement the “Show More” button on the homepage to display additional property listings.

Create a JSON Data File: Create a file named state-object.json in the src directory (or a suitable location in your project). This file will contain an array of JSON objects, each representing a property listing. Populate this file with data extracted from the Figma design (listing image URLs, titles, descriptions, etc.). Ensure image URLs are correctly referenced (initially using http://localhost:3000 as a placeholder if images are not yet hosted).

JSON (JavaScript Object Notation): A lightweight data-interchange format that is easy for humans to read and write and easy for machines to parse and generate. It is commonly used for data transmission in web applications.

Create a Card List Component in Looi Builder:
- In Looi Builder, navigate to the homepage design.
- Select the parent container element that holds all the property listing items (e.g., an element named “homes”).
- Go to “Settings” -> “Code Components & Props” -> “Make Your Own Component.”
- Name the component “CardList” and click “Create.”
Create a State Variable in Looi Builder:
- In Looi Builder, go to “Settings” -> “Data Binding.”
- Click “Create State Variable.”
- Name the state variable “cardState” and set its data type to “Array.”
- Paste the content of your state-object.json file into the state variable’s value field. Replace placeholder image URLs with http://localhost:3000 if necessary. Save the state variable.
Bind Data to the Card List Component:
- Select the “CardList” component in Looi Builder.
- Go to “Bind Data.”
- Click the ”+” icon to add a data binding.
- Choose the first listing item within the “CardList.”
- Select “Repeat” as the binding type.
- Choose “cardState” as the data source.
- Looi Builder will automatically populate the props for the listing item component based on the data in cardState. Save the data binding.
Sync Changes to GitHub: Sync your Looi Builder project to your GitHub repository to reflect these changes in your local codebase.
Pull Changes Locally: In your terminal, run git pull to fetch the latest changes from GitHub to your local project.
Modify CardList Component Code:
- Open the CardList component file (likely in src/components/CardList.jsx or similar, depending on your project structure) in your code editor.
- Import useState from React: import React, { useState } from 'react';.
- In the CardList component function, add a useState hook to manage the “show more” state:
```
const [showAll, setShowAll] = useState(false);
```
- Modify the data mapping logic to conditionally render listings based on the showAll state. For example, use Array.slice() to initially display a limited number of listings and then display all listings when showAll is true.
- Pass the setShowAll function as a prop to the “Show More” button component.
Modify “Show More” Button Component Code:
- Open the “Show More” button component file (likely in src/components/ShowMoreButton.jsx or similar).
- Receive the setShowAll prop in the component function.
- Implement the onClick handler for the button to toggle the showAll state using setShowAll(!showAll).

By following these steps, you will have implemented basic “Show More” functionality, demonstrating how to integrate data and interactivity into your AI-generated frontend code.

Backend Development and User Authentication

To create a fully functional application, we need to develop a backend to manage data persistence and user authentication. We will use Node.js with Express for the backend and MongoDB Atlas as our cloud database.

Setting up the Node.js Backend

Create index.js: In the root directory of your project, create a new file named index.js. This file will be the entry point for your Node.js backend.
Initialize Backend Code: In index.js, add the following basic setup for an Express server:
```
const express = require('express');
const cors = require('cors');
require('dotenv').config(); // Load environment variables from .env file

const app = express();
const port = process.env.PORT || 8000; // Use environment port or default to 8000

app.use(cors()); // Enable Cross-Origin Resource Sharing (CORS)
app.use(express.json()); // Parse JSON request bodies

app.listen(port, () => {
    console.log(`Server is listening on port: ${port}`);
});
```
API Endpoint: A specific URL that a server exposes to provide access to its data or functionality. APIs (Application Programming Interfaces) define how different software components should interact.

Backend: The server-side portion of a web application. It handles data storage, business logic, and API endpoints that the frontend interacts with.

Frontend: The client-side portion of a web application that users interact with directly in their web browser. It is responsible for the user interface and user experience.

Database: A structured collection of data that is stored and accessed electronically. Databases are used to persist and manage application data.

Authentication: The process of verifying the identity of a user or device. It ensures that only authorized users can access specific parts of an application or system.

Cookies: Small pieces of data that websites store on a user’s computer. They are used to remember information about the user, such as login status or preferences.

JWT (JSON Web Token): A standard for securely transmitting information as a JSON object. JWTs are commonly used for authentication and authorization in web applications.

bcrypt: A password-hashing function designed to be computationally expensive to crack. It is widely used for securely storing user passwords in databases.

MongoDB Atlas: A cloud-hosted database service provided by MongoDB. It offers a fully managed MongoDB database in the cloud, simplifying database setup and management.

No Demon (nodemon, likely a typo in transcript): A utility that automatically restarts a Node.js application when file changes are detected. It is useful for development to avoid manually restarting the server after each code modification. The correct term is likely nodemon.

Express: A minimal and flexible Node.js web application framework that provides a robust set of features for building web and mobile applications.

Course (likely CORS - Cross-Origin Resource Sharing, a typo): CORS (Cross-Origin Resource Sharing) is a browser security feature that restricts web pages from making requests to a different domain than the one that served the web page. CORS needs to be configured on the backend to allow requests from the frontend domain.

EnV File: A configuration file, typically named .env, used to store environment variables. Environment variables are key-value pairs that can configure application behavior without hardcoding values directly into the code. This is often used for sensitive information like API keys or database connection strings.

URI/Connection String: A string that specifies the location of a database server and authentication credentials required to connect to it. In MongoDB, it typically includes the database protocol, hostname, port, username, password, and database name.
Install Backend Dependencies: In your terminal, navigate to the project root and run npm install express cors dotenv mongodb bcrypt jsonwebtoken. This installs the necessary Node.js packages:
- express: For creating the web server and defining routes.
- cors: To handle Cross-Origin Resource Sharing (CORS) for frontend-backend communication.
- dotenv: To load environment variables from a .env file.
- mongodb: The official MongoDB driver for Node.js.
- bcrypt: For password hashing.
- jsonwebtoken: For generating and verifying JSON Web Tokens (JWTs) for authentication.
Create .env File: In the project root, create a file named .env. Add your MongoDB Atlas connection string and a secret key for JWT signing to this file:
```
URI="your_mongodb_atlas_connection_string"
JWT_SECRET="your_secret_jwt_key"
```
Replace "your_mongodb_atlas_connection_string" with your actual MongoDB Atlas connection string and "your_secret_jwt_key" with a strong, randomly generated secret key. Keep this .env file secure and do not commit it to version control.
Update package.json Scripts: In your package.json file, update the scripts section to include scripts for starting both the frontend and backend servers concurrently:
```
"scripts": {
  "start": "react-scripts start",
  "build": "react-scripts build",
  "test": "react-scripts test",
  "eject": "react-scripts eject",
  "start:frontend": "npm start",
  "start:backend": "nodemon index.js"
},
```
REST API (Representational State Transfer API): An architectural style for designing networked applications. REST APIs use standard HTTP methods (GET, POST, PUT, DELETE) to access and manipulate resources.

HTTP Methods (POST): Verbs used in HTTP requests to indicate the desired action. POST is typically used to send data to a server to create a new resource.

JSON Stringify/Parse: JSON.stringify() is a JavaScript method to convert a JavaScript object into a JSON string. JSON.parse() is a JavaScript method to convert a JSON string back into a JavaScript object.
Run Backend and Frontend: Open two terminals. In one terminal, navigate to your project directory and run npm run start:frontend to start the React frontend. In the other terminal, run npm run start:backend to start the Node.js backend. Ensure both servers are running without errors.

MongoDB Atlas Setup:
- Go to mongodb.com/atlas and sign up or log in to MongoDB Atlas.
- Create a new project and a free-tier cluster (if you don’t have one already).
- Create a database user with appropriate permissions.
- Whitelist your IP address (or allow access from anywhere for development purposes, but be cautious in production).
- Get your MongoDB Atlas connection string.

Signup API Endpoint (/signup): In index.js, add a POST route for /signup to handle user registration:

const { MongoClient } = require('mongodb');
const bcrypt = require('bcrypt');
const jwt = require('jsonwebtoken');
const uuidv4 = require('uuid').v4; // Import UUID v4

const uri = process.env.URI;
const jwtSecret = process.env.JWT_SECRET;

app.post('/signup', async (req, res) => {
    const client = new MongoClient(uri);

    try {
        await client.connect();
        const database = client.db('locoData'); // Replace 'locoData' with your database name
        const usersCollection = database.collection('users');

        const { email, password } = req.body;

        const existingUser = await usersCollection.findOne({ email });
        if (existingUser) {
            return res.status(409).send('User already exists. Please log in.');
        }

        const saltRounds = 10;
        const hashedPassword = await bcrypt.hash(password, saltRounds);
        const sanitizedEmail = email.toLowerCase();
        const userId = uuidv4(); // Generate a unique user ID

        const userData = {
            userId: userId, // Include the generated user ID
            email: sanitizedEmail,
            hashedPassword: hashedPassword,
        };

        const insertedUser = await usersCollection.insertOne(userData);

        const token = jwt.sign({ userId: userId, email: sanitizedEmail }, jwtSecret, { expiresIn: '6h' }); // Include userId in token payload

        res.status(201).json({ token, userId: userId }); // Send back token and userId
    } catch (error) {
        console.error('Signup error:', error);
        res.status(500).send('Error signing up user.');
    } finally {
        await client.close();
    }
});

REST API (Representational State Transfer API): An architectural style for designing networked applications. REST APIs use standard HTTP methods (GET, POST, PUT, DELETE) to access and manipulate resources.

HTTP Methods (POST): Verbs used in HTTP requests to indicate the desired action. POST is typically used to send data to a server to create a new resource.

JSON Stringify/Parse: JSON.stringify() is a JavaScript method to convert a JavaScript object into a JSON string. JSON.parse() is a JavaScript method to convert a JSON string back into a JavaScript object.

Login API Endpoint (/login): Add a POST route for /login to handle user login:

app.post('/login', async (req, res) => {
    const client = new MongoClient(uri);

    try {
        await client.connect();
        const database = client.db('locoData'); // Replace 'locoData' with your database name
        const usersCollection = database.collection('users');

        const { email, password } = req.body;

        const user = await usersCollection.findOne({ email });
        if (!user) {
            return res.status(401).send('Invalid credentials.'); // Unauthorized
        }

        const isPasswordCorrect = await bcrypt.compare(password, user.hashedPassword);
        if (!isPasswordCorrect) {
            return res.status(401).send('Invalid credentials.'); // Unauthorized
        }

        const token = jwt.sign({ userId: user.userId, email: user.email }, jwtSecret, { expiresIn: '6h' }); // Include userId in token payload

        res.status(200).json({ token, userId: user.userId }); // Send back token and userId
    } catch (error) {
        console.error('Login error:', error);
        res.status(500).send('Error logging in.');
    } finally {
        await client.close();
    }
});

Frontend Integration (Signup and Login Pages):
- In your React frontend code (e.g., SignupPage.jsx, LoginPage.jsx), update the fetch calls in your signup and login functions to point to your backend API endpoints (http://localhost:8000/signup and http://localhost:8000/login, respectively).
- In the frontend, after successfully receiving a token and user ID from the backend upon signup or login, store the token and user ID in cookies using the react-cookie library.
- Implement logic to check for the presence of the token in cookies to control user authentication state and route access (as demonstrated in the transcript’s example).
Git Pull/Push: git pull is a Git command to fetch changes from a remote repository and merge them into your local branch. git push is a Git command to upload your local commits to a remote repository.
Test Signup and Login: Run both your frontend and backend servers. Navigate to the signup page in your browser (http://localhost:3000/signup). Create a new user account. Then, try logging in with the created credentials on the login page (http://localhost:3000/login). Verify that signup and login are successful and that tokens and user IDs are correctly stored in cookies.

Deployment Overview

To make your application accessible online, you need to deploy both the frontend and backend.

Frontend Deployment (Netlify):

Netlify is a popular platform for deploying static frontend applications.
Connect your Netlify account to your GitHub repository containing your frontend code.
Configure Netlify to build and deploy your React application automatically whenever you push changes to your repository.
Netlify provides a free tier suitable for learning and small projects.

Backend Deployment (Separate Server or Platform-as-a-Service):

Backend deployment is more complex than frontend deployment. You need a server environment to run your Node.js backend.
Options include:
- Platform-as-a-Service (PaaS) providers: Heroku, AWS Elastic Beanstalk, Google App Engine, etc. These platforms simplify backend deployment and management.
- Virtual Private Server (VPS): You can rent a VPS and manually configure and deploy your Node.js backend. This offers more control but requires server administration skills.
Consult the documentation for your chosen deployment platform for detailed instructions on deploying a Node.js application.
Netlify Documentation: While Netlify is primarily for frontends, it offers some backend functionalities (like serverless functions). However, for a full Node.js backend, you’ll likely need a separate hosting solution. Review Netlify’s documentation and support forums for guidance on backend deployment options that integrate well with Netlify-hosted frontends.

Netlify Documentation: Official documentation and guides provided by Netlify, a platform for deploying and hosting web applications. It contains information on features, configurations, and best practices for using Netlify services.

Important Considerations for Deployment:

Environment Variables: Securely manage environment variables (especially your MongoDB connection string and JWT secret) in your deployment environment. Do not hardcode sensitive information directly in your code. Use platform-specific mechanisms for setting environment variables (e.g., Netlify environment variables, Heroku config vars).
CORS Configuration: Ensure your backend is properly configured for CORS to allow requests from your deployed frontend domain.
Database Security: Secure your MongoDB Atlas database by configuring network access rules and authentication properly.

Further Exploration

This chapter provides a foundational understanding of using AI-powered tools like Looi Lightning and Loco AI to accelerate frontend development and integrate with backend systems. To further enhance your skills and expand the “Local Host” application, consider exploring the following:

Implement Full CRUD Operations: Extend the backend API to support Create, Read, Update, and Delete (CRUD) operations for property listings and user data.
Implement Property Filtering and Search: Integrate the filter functionality designed in Figma into your application, allowing users to search and filter properties based on various criteria.
Map Integration: Integrate a map library (e.g., Leaflet, Google Maps) to display property locations based on latitude and longitude data, as designed in Figma.
Image Hosting: Set up a cloud-based image hosting service (e.g., AWS S3, Cloudinary) to store and serve property images efficiently.
Testing and Refinement: Implement automated testing (unit tests, integration tests) to ensure code quality and application stability. Refine the user interface and user experience based on user feedback and testing.
Advanced Authentication: Explore more advanced authentication methods, such as social logins (OAuth 2.0), and implement features like password reset and account management.
State Management: For larger applications, consider using a state management library like Redux or Context API to manage application state more effectively.
Explore Other AI-Powered Development Tools: Investigate other AI-assisted development tools and platforms that can further streamline your development workflow, such as AI code completion tools, AI-powered testing tools, and low-code/no-code platforms.

Glossary of Terms