Refactor assets bundler and split Javascript files

ui/static/js/unread_counter_handler.js

@@ -0,0 +1,33 @@
+class UnreadCounterHandler {
+    static decrement(n) {
+        this.updateValue((current) => {
+            return current - n;
+        });
+    }
+
+    static increment(n) {
+        this.updateValue((current) => {
+            return current + n;
+        });
+    }
+
+    static updateValue(callback) {
+        let counterElements = document.querySelectorAll("span.unread-counter");
+        counterElements.forEach((element) => {
+            let oldValue = parseInt(element.textContent, 10);
+            element.innerHTML = callback(oldValue);
+        });
+
+        if (window.location.href.endsWith('/unread')) {
+            let oldValue = parseInt(document.title.split('(')[1], 10);
+            let newValue = callback(oldValue);
+
+            document.title = document.title.replace(
+                /(.*?)\(\d+\)(.*?)/,
+                function (match, prefix, suffix, offset, string) {
+                    return prefix + '(' + newValue + ')' + suffix;
+                }
+            );
+        }
+    }
+}