Implementing Infinite Scrolling Efficiently

Phong Lam from Walmart Global Tech tackles a problem every mobile dev faces: infinite scroll that doesn't tank performance. His solution? Stop rendering everything and start being strategic.

Infinite scrolling seems simple until you're rendering thousands of DOM nodes and watching your app crawl. Lam breaks down why the naive approach fails and presents a windowing technique that only renders what users actually see, dramatically reducing memory overhead.

Key Takeaways

• Traditional infinite scroll creates hundreds or thousands of DOM nodes
• Windowing technique renders only visible items plus small buffer
• Dynamically adjusts container height and repositions items on scroll
• Reduces interaction cost by eliminating pagination clicks on mobile

The article includes working code for detecting scroll position and calculating which items to render, but watch out for the accessibility gotcha mentioned in the comments.