Intersection Observer - Image lazy load

intersection-observer.js

// Get all of the images that are marked up to lazy load
const images = document.querySelectorAll('.js-lazy-image');
const config = {
  // If the image gets within 50px in the Y axis, start the download.
  rootMargin: '50px 0px',
  threshold: 0.01
};

// The observer for the images on the page
let observer = new IntersectionObserver(onIntersection, config);
images.forEach(image => {
  observer.observe(image);
});