Virtual Scroll Library

A React hook for implementing virtual scrolling with infinite loading capabilities.

Demo

Check out the live demo of the Virtual Scroll Library in action: Virtual Scroll Library Demo

GitHub Repository

For the latest updates, issue reporting, and contribution guidelines, please visit our GitHub repository: Virtual Scroll Library on GitHub

Installation

You can install the Virtual Scroll Library using npm or yarn:

npm install virtual-scroll-library
# or
yarn add virtual-scroll-library

Usage

Here's a complete example of how to use the useVirtualScroll hook in your React component:

import React from "react";
import { useVirtualScroll } from "virtual-scroll-library";

interface Post {
  id: number;
  title: string;
  content: string;
}

const VirtualScrollExample: React.FC = () => {
  const fetchPosts = async (page: number): Promise<Post[]> => {
    // Simulating an API call
    await new Promise((resolve) => setTimeout(resolve, 500));
    return Array.from({ length: 10 }, (_, i) => ({
      id: (page - 1) * 10 + i + 1,
      title: `Post ${(page - 1) * 10 + i + 1}`,
      content: `This is the content of post ${(page - 1) * 10 + i + 1}...`,
    }));
  };

  const { allItems, isLoading, containerRef } = useVirtualScroll<Post>({
    fetchItems: fetchPosts,
    threshold: 200, // 200px before the end of the list
  });

  return (
    <div
      ref={containerRef}
      style={{ height: "600px", overflow: "auto", padding: "20px" }}
    >
      {allItems.map((post) => (
        <div
          key={post.id}
          style={{
            marginBottom: "20px",
            padding: "10px",
            border: "1px solid #ccc",
          }}
        >
          <h2>{post.title}</h2>
          <p>{post.content}</p>
        </div>
      ))}
      {isLoading && <div>Loading more posts...</div>}
    </div>
  );
};

export default VirtualScrollExample;

API

useVirtualScroll<T>

A hook that implements virtual scrolling functionality.

Parameters

The hook accepts an object with the following properties:

• fetchItems: (page: number) => Promise<T[]>: A function that fetches items for a given page.
• initialItems?: T[]: (Optional) An initial set of items to display.
• itemsPerPage?: number: (Optional) The number of items to fetch per page. Default is 10.
• threshold?: number: (Optional) The distance from the bottom of the list (in pixels) at which to trigger loading more items. Default is 200.

Return Value

The hook returns an object with the following properties:

• allItems: T[]: An array containing all loaded items.
• newLoadedItems: T[]: An array containing only the most recently loaded items.
• isLoading: boolean: A boolean indicating whether new items are currently being loaded.
• containerRef: React.RefObject<HTMLDivElement>: A ref to be attached to the scrollable container.

TypeScript Support

This library is written in TypeScript and provides full type definitions. The useVirtualScroll hook is generic, allowing you to specify the type of your list items for improved type safety.

Performance Considerations

• The virtual scroll implementation efficiently renders only the visible items, making it suitable for large lists.
• Consider implementing memoization techniques (e.g., React.memo, useMemo) for child components to optimize rendering performance.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License.