Release 3.15 (PR #6131)

Release 3.15

assets/js/lazyload-css.js

@@ -0,0 +1,80 @@
+function rocket_css_lazyload_launch() {
+
+	const usable_pairs = typeof rocket_pairs === 'undefined' ? [] : rocket_pairs;
+
+
+	const styleElement = document.querySelector('#wpr-lazyload-bg');
+
+	const threshold = rocket_lazyload_css_data.threshold || 300;
+
+	const observer = new IntersectionObserver(entries => {
+		entries.forEach(entry => {
+			if (entry.isIntersecting) {
+				const pairs = usable_pairs.filter(s => entry.target.matches(s.selector));
+				pairs.map(pair => {
+					if (pair) {
+						styleElement.innerHTML += pair.style;
+						pair.elements.forEach(el => {
+							el.setAttribute('data-rocket-lazy-bg', 'loaded');
+							// Stop observing the target element
+							observer.unobserve(el);
+						});
+					}
+				})
+			}
+		});
+	}, {
+		rootMargin: threshold + 'px'
+	});
+
+	function lazyload(e = []) {
+
+		const pass = e.length === 0 || e.find(e =>  e.type !== 'attributes' || e.attributeName === 'class');
+
+		if(! pass ) {
+			return;
+		}
+
+		usable_pairs.forEach(pair => {
+			try {
+
+				const elements = document.querySelectorAll(pair.selector);
+				elements.forEach(el => {
+					if(el.getAttribute('data-rocket-lazy-bg') === 'loaded') {
+						return;
+					}
+					observer.observe(el);
+					// Save el in the pair object (create a new empty array if it doesn't exist)
+					(pair.elements ||= []).push(el);
+				});
+			} catch (error) {
+				console.error(error);
+			}
+		});
+	}
+
+	lazyload();
+
+	const observe_DOM = (function(){
+		const MutationObserver = window.MutationObserver;
+
+		return function( obj, callback ){
+			if( !obj || obj.nodeType !== 1 ) return;
+
+			// define a new observer
+			const mutationObserver = new MutationObserver(callback);
+
+			// have the observer observe for changes in children
+			mutationObserver.observe( obj, { attributes: true, childList:true, subtree:true })
+			return mutationObserver
+
+		}
+
+	})()
+
+	const body = document.querySelector('body');
+
+	observe_DOM(body, lazyload)
+}
+
+rocket_css_lazyload_launch();