Intersection Observer API
The Intersection Observer API is a web API that allows developers to asynchronously observe changes in the intersection of a target element with an ancestor element or the viewport. It provides a way to efficiently detect when elements become visible or hidden, enabling performance optimizations like lazy loading of images or infinite scrolling without relying on scroll event listeners that can cause performance bottlenecks.
Developers should learn and use the Intersection Observer API when building modern web applications that require efficient handling of element visibility, such as implementing lazy loading for images or content to improve page load times and reduce bandwidth usage. It is particularly useful for creating responsive interfaces with infinite scrolling, triggering animations when elements enter the viewport, or managing ad impressions without heavy DOM manipulation or scroll event handlers that degrade performance.