Check if a node is in the viewport

const image = document.querySelector('.animate-me');

observer = new IntersectionObserver((entries) => {
  const [ myImg ] = entries;
    if (myImg.intersectionRatio > 0) {
      myImg.target.classList.add('fancy');
    } else {
      myImg.target.classList.remove('fancy');
    }
});


observer.observe(image);

Source

https://github.com/roeib/JavaScript-snippets#check-if-a-node-is-in-the-viewport