Add experimental infinite scroll

public/js/infiniteScroll.js

@@ -0,0 +1,54 @@
+function insertBeforeLast(node, elem) {
+    node.insertBefore(elem, node.childNodes[node.childNodes.length - 2]);
+}
+
+function getLoadMore(doc) {
+    return doc.querySelector('.show-more:not(.timeline-item)');
+}
+
+window.onload = function() {
+    const isTweet = window.location.pathname.indexOf("/status/") !== -1;
+    const containerClass = isTweet ? ".replies" : ".timeline";
+    const itemClass = isTweet ? ".thread-line" : ".timeline-item";
+
+    var html = document.querySelector("html");
+    var container = document.querySelector(containerClass);
+    var loading = false;
+
+    window.addEventListener('scroll', function() {
+        if (loading) return;
+        if (html.scrollTop + html.clientHeight >= html.scrollHeight - 3000) {
+            loading = true;
+            var topRef = document.querySelector('.top-ref');
+            var loadMore = getLoadMore(document);
+            if (loadMore == null) return;
+
+            loadMore.children[0].text = "Loading...";
+
+            var url = new URL(loadMore.children[0].href);
+            window.history.pushState('', '', url.toString());
+            url.searchParams.append('scroll', 'true');
+
+            fetch(url.toString()).then(function (response) {
+	            return response.text();
+            }).then(function (html) {
+                var parser = new DOMParser();
+                var doc = parser.parseFromString(html, 'text/html');
+                loadMore.remove();
+
+                for (var item of doc.querySelectorAll(itemClass)) {
+                    if (item.className == "timeline-item show-more") continue;
+                    if (isTweet) container.appendChild(item);
+                    else insertBeforeLast(container, item);
+                }
+
+                if (isTweet) container.appendChild(getLoadMore(doc));
+                else insertBeforeLast(container, getLoadMore(doc));
+                loading = false;
+            }).catch(function (err) {
+	            console.warn('Something went wrong.', err);
+                loading = true;
+            });
+        }
+    });
+};