Update ajax to use intersection observer

src/js/core/_core.js

@@ -185,6 +185,13 @@ module.exports = {
 
 		document.querySelectorAll("article").forEach((a) => {
 			if ( a.getAttribute("data-template") != "none" ) {
+
+				const observer = new IntersectionObserver((articles, { threshold: 0, rootMargin: 50vh}) => {
+					articles.forEach(article => {
+						let a = article.target;
+
+						if (article.isIntersecting) {
+
 							let path = a.getAttribute("data-path");
 							path = "patterns/" + 
 							 		(a.getAttribute("data-core") == "true" ? 
@@ -267,6 +274,13 @@ module.exports = {
 							};
 							ajx.open("GET", path, ASYNC);
 							ajx.send();
+
+						}
+					})
+				})
+
+				observer.observe(a);
+
 			}
 		})