Pagination patterns in Supabase - Mini Project: Build & Apply

Pagination Patterns with Supabase

📖 Scenario: You are building a simple web app that shows a list of books stored in a Supabase database. The list can be very long, so you want to show only a few books at a time and let users move through pages.

🎯 Goal: Create a pagination system using Supabase JavaScript client that fetches books 5 at a time. You will first set up the initial data query, then add a page size variable, then fetch the correct page of books, and finally add the logic to move to the next page.

📋 What You'll Learn

Use Supabase JavaScript client to query the 'books' table

Fetch 5 books per page

Implement pagination using range method

Create a variable to track the current page number

Add logic to fetch the next page of books

💡 Why This Matters

🌍 Real World

Pagination is essential in apps that show large lists of data, like product catalogs or user lists, to improve performance and user experience.

💼 Career

Understanding how to implement pagination with cloud databases like Supabase is a common task for frontend and backend developers working with modern web apps.

1

Set up Supabase client and initial query

Create a constant called supabase that initializes the Supabase client with URL 'https://xyzcompany.supabase.co' and anon key 'public-anon-key'. Then create an async function called fetchBooks that queries the 'books' table and selects all columns.

Supabase

// Initialize Supabase client and create fetchBooks function
// Your code here

Need a hint?

Use createClient from Supabase to connect. Then use supabase.from('books').select('*') inside the async function.

2

Add page size configuration

Add a constant called PAGE_SIZE and set it to 5. This will control how many books we fetch per page.

Supabase

import { createClient } from '@supabase/supabase-js';

const supabase = createClient('https://xyzcompany.supabase.co', 'public-anon-key');

const PAGE_SIZE = 5

async function fetchBooks() {
  const { data, error } = await supabase.from('books').select('*');
  if (error) {
    throw error;
  }
  return data;
}

// Your code here

Need a hint?

Just add const PAGE_SIZE = 5; after the Supabase client initialization.

3

Fetch books for a specific page

Add a constant called currentPage and set it to 1. Then update the fetchBooks function to use range to fetch books for the current page. Use range((currentPage - 1) * PAGE_SIZE, currentPage * PAGE_SIZE - 1) in the query.

Supabase

import { createClient } from '@supabase/supabase-js';

const supabase = createClient('https://xyzcompany.supabase.co', 'public-anon-key');

const PAGE_SIZE = 5;
const currentPage = 1

async function fetchBooks() {
  const { data, error } = await supabase.from('books').select('*').range((currentPage - 1) * PAGE_SIZE, currentPage * PAGE_SIZE - 1);
  if (error) {
    throw error;
  }
  return data;
}

// Your code here

Need a hint?

Use range with calculated start and end indexes based on currentPage and PAGE_SIZE.

4

Add function to fetch next page

Create an async function called fetchNextPage that increases currentPage by 1 and then calls fetchBooks to get the next set of books.

Supabase

import { createClient } from '@supabase/supabase-js';

const supabase = createClient('https://xyzcompany.supabase.co', 'public-anon-key');

const PAGE_SIZE = 5;
let currentPage = 1;

async function fetchBooks() {
  const { data, error } = await supabase.from('books').select('*').range((currentPage - 1) * PAGE_SIZE, currentPage * PAGE_SIZE - 1);
  if (error) {
    throw error;
  }
  return data;
}

// Your code here

Need a hint?

Change currentPage to let so it can be updated. Then create fetchNextPage that increments currentPage and calls fetchBooks.