archive-lazy.js

// Credit: https://web.dev/articles/lazy-loading-video
document.addEventListener("DOMContentLoaded", function () {
	var lazyVideos = [].slice.call(document.querySelectorAll("video.lazy"));

	if ("IntersectionObserver" in window) {
		var lazyVideoObserver = new IntersectionObserver(function (entries, observer) {
			entries.forEach(function (video) {
				if (video.isIntersecting && window.innerWidth > 600) {
					for (var source in video.target.children) {
						var videoSource = video.target.children[source];
						if (typeof videoSource.tagName === "string" && videoSource.tagName === "SOURCE") {
							videoSource.src = videoSource.dataset.src;
						}
					}

					video.target.load();
					video.target.classList.remove("lazy");
					lazyVideoObserver.unobserve(video.target);
				}
			});
		});

		lazyVideos.forEach(function (lazyVideo) {
			lazyVideoObserver.observe(lazyVideo);
		});
	}
});