setup intersection observer and execute logic when intersected

setupInterSectionObserver.js

const imageObserver = new IntersectionObserver((entries, imgObserver) => {
  entries.forEach((entry) => {
    if (entry.isIntersecting) {
      const element = entry.target;
      element.src = element.getAttribute("dataSrc");
      element.removeAttribute("dataSrc");
      imgObserver.unobserve(element);
    }
  });
});
const imgArr = document.querySelectorAll("img");
imgArr.forEach((item) => {
  imageObserver.observe(item);
});