A practical guide to using Intersection Observer for component and image lazy-loading in React, with patterns for scaling to hundreds of list items, infinite scroll, and real-world performance metrics.
Introduction In today’s digital landscape, users expect instant gratification. A page that loads in a split second feels fast, trustworthy, and professional, while a sluggish page drives visitors away and hurts conversion rates. One of the most effective techniques to shave milliseconds—sometimes seconds—off perceived load time is lazy loading. Lazy loading (sometimes called deferred loading or on‑demand loading) postpones the retrieval of resources until they are actually needed. By doing so, you reduce the amount of data transferred during the initial page request, lower memory consumption, and give browsers (or native runtimes) more breathing room to render the most important content first. ...