1. Set Up Supabase Account and Project

• Go to the Supabase website and sign up for an account if you don't have one already.
• Once logged in, create a new project. You'll need to provide a project name, password, and database region.

2. Configure Database Tables

• Navigate to the `Database` section of your project dashboard.
• Create a table for `products` with relevant columns like `id`, `name`, `description`, `price`, and `image_url`.
• Create another table for `cart_items` with columns like `id`, `user_id`, `product_id`, `quantity`, and `added_at`.

3. Initialize Supabase in Your Frontend

• If using JavaScript, install the Supabase client library in your project using npm: npm install @supabase/supabase-js.
• Create a new JavaScript file, e.g., `supabaseClient.js`, and initialize the Supabase client:

  import { createClient } from '@supabase/supabase-js';
  
  const supabaseUrl = 'your-supabase-url';
  const supabaseKey = 'your-supabase-key';
  const supabase = createClient(supabaseUrl, supabaseKey);
  export default supabase;

  
  

4. Fetch Products from Database

• Write a function to fetch products from the `products` table:

  async function fetchProducts() {
    let { data: products, error } = await supabase
      .from('products')
      .select('\*');
  
    if (error) console.error('Error fetching products:', error);
    else return products;
  }

  
  


• Display these products in your frontend component.

5. Add Products to Cart

• Create a function to add a product to the `cart_items` table:

  async function addToCart(userId, productId, quantity) {
    const { data, error } = await supabase
      .from('cart\_items')
      .insert([{ user_id: userId, product_id: productId, quantity: quantity }]);
  
    if (error) console.error('Error adding to cart:', error);
    else console.log('Added to cart:', data);
  }

  
  


• Bind this function to an "Add to Cart" button in your product display component.

6. Display Cart Items

• Create a function to fetch items from the `cart_items` table:

  async function fetchCartItems(userId) {
    let { data: cartItems, error } = await supabase
      .from('cart\_items')
      .select('\*')
      .eq('user\_id', userId);
  
    if (error) console.error('Error fetching cart items:', error);
    else return cartItems;
  }

  
  


• Display these cart items in your cart component.

7. Update and Remove Cart Items

• Create functions for updating and removing cart items:

  async function updateCartItem(itemId, newQuantity) {
    const { data, error } = await supabase
      .from('cart\_items')
      .update({ quantity: newQuantity })
      .eq('id', itemId);
  
    if (error) console.error('Error updating cart item:', error);
    else console.log('Cart item updated:', data);
  }
  async function removeCartItem(itemId) {
    const { data, error } = await supabase
      .from('cart_items')
      .delete()
      .eq('id', itemId);
    if (error) console.error('Error removing cart item:', error);
    else console.log('Cart item removed:', data);
  }

  
  


• Bind these functions to appropriate buttons within your cart component.

8. Handle User Authentication

• Utilize Supabase's authentication feature to manage users. Refer to the [Supabase Auth Documentation](https://supabase.io/docs/guides/auth) for setup and usage.
• Ensure that user actions (e.g., adding to cart, fetching cart items) are tied to the authenticated user's ID.

9. Deploy Your Application

• Deploy your frontend application using your preferred hosting provider (e.g., Vercel, Netlify).
• Ensure your Supabase instance is live and accessible from your deployed application.