Infinite scrolling has become a popular UI pattern, especially in web applications that involve displaying large amounts of content. The concept of infinite scrolling is to dynamically load more data as the user scrolls down the page, providing a seamless and uninterrupted browsing experience.

In this tutorial, we will create a custom useInfiniteScroll hook using React that will handle the logic for infinite scrolling. Let’s get started!

Table of Contents

• What is Infinite Scrolling?
• Creating the useInfiniteScroll Hook
• Using the useInfiniteScroll Hook
• Conclusion

What is Infinite Scrolling?

Infinite scrolling is a technique in web design that allows content to be loaded continuously as the user scrolls down the page, eliminating the need for traditional pagination. This approach provides a more fluid and engaging user experience, allowing users to explore content effortlessly without any interruptions.

Creating the useInfiniteScroll Hook

Let’s start by creating a new file called useInfiniteScroll.js and define our custom hook inside it. The useInfiniteScroll hook will handle the logic for detecting when the user has reached the bottom of the page and trigger a callback function to load more data.

import { useEffect } from 'react';

const useInfiniteScroll = (callback) => {
  useEffect(() => {
    const handleScroll = () => {
      if (
        window.innerHeight + document.documentElement.scrollTop
        === document.documentElement.scrollHeight
      ) {
        callback();
      }
    };

    window.addEventListener('scroll', handleScroll);
    return () => {
      window.removeEventListener('scroll', handleScroll);
    };
  }, [callback]);
};

export default useInfiniteScroll;

In the above code, we import the useEffect hook from React and define the useInfiniteScroll hook as a function that takes a callback function as an argument. Inside the useEffect hook, we attach an event listener to the scroll event and check if the user has scrolled to the bottom of the page by comparing the window’s inner height plus the scroll position to the total height of the document. If the condition is met, the callback function is invoked.

Using the useInfiniteScroll Hook

Now that we have our useInfiniteScroll hook ready, let’s see how we can use it in a component. Assuming we have a component called PostList that displays a list of posts, and we want to load more posts when the user reaches the end of the page.

import React, { useState, useEffect } from 'react';
import useInfiniteScroll from './useInfiniteScroll';

const PostList = () => {
  const [posts, setPosts] = useState([]);
  const [page, setPage] = useState(1);

  const fetchPosts = async () => {
    const response = await fetch(`https://api.example.com/posts?page=${page}`);
    const data = await response.json();
    setPosts((prevPosts) => [...prevPosts, ...data.posts]);
    setPage((prevPage) => prevPage + 1);
  };

  useInfiniteScroll(fetchPosts);

  return (
    <div>
      {posts.map((post) => (
        <div key={post.id}>{post.title}</div>
      ))}
    </div>
  );
};

export default PostList;

In the PostList component, we define a state variable posts to store the loaded posts and page to keep track of the current page number. The fetchPosts function is responsible for fetching more posts using an API endpoint. When the fetchPosts function is called, we append the new posts to the existing posts array and increment the page number.

We then call the useInfiniteScroll hook and pass the fetchPosts function as the callback. This will trigger the fetchPosts function whenever the user reaches the bottom of the page.

Finally, we render the list of posts using the map function, displaying the title of each post.

Conclusion

In this tutorial, we created a custom useInfiniteScroll hook using React to handle the logic for infinite scrolling. By encapsulating the scroll event listener and callback function in a reusable hook, we can easily implement infinite scrolling in our components and provide a more interactive user experience.

Implementing infinite scrolling can greatly improve the performance and usability of web applications with large amounts of content. As always, experiment with the code and customize it to fit your specific requirements. Happy coding!

#react #infinite-scroll