some minor optimalizations

lib/dependencyLibs/events.js

@@ -31,7 +31,7 @@ function on(events, handler) {
         if (elem.addEventListener) { // all browsers except IE before version 9
             elem.addEventListener(ev, handler, false);
         } else if (elem.attachEvent) { // IE before version 9
-            elem.attachEvent("on" + ev, handler);
+            elem.attachEvent(`on${ev}`, handler);
         }
         eventRegistry[ev] = eventRegistry[ev] || {};
         eventRegistry[ev][namespace] = eventRegistry[ev][namespace] || [];
@@ -42,14 +42,10 @@ function on(events, handler) {
         var eventRegistry = this[0].eventRegistry,
             elem = this[0];
 
-
-        var _events = events.split(" ");
-        for (var endx = 0; endx < _events.length; endx++) {
-            var nsEvent = _events[endx].split("."),
-                ev = nsEvent[0],
-                namespace = nsEvent[1] || "global";
+        events.split(" ").forEach((event) => {
+            const [ev, namespace = "global"] = event.split(".");
             addEvent(ev, namespace);
-        }
+        });
     }
     return this;
 }

lib/mask-lexer.js

@@ -17,7 +17,7 @@ function generateMaskSet(opts, nocache) {
             let optionalRegex = "(.)\\[([^\\]]*)\\]", // "(?<p1>.)\\[(?<p2>[^\\]]*)\\]", remove named capture group @2428
                 maskMatches = mask.match(new RegExp(optionalRegex, "g"));
             maskMatches && maskMatches.forEach((m, i) => {
-                let groups = m.split("["), p1 = groups[0], p2 = groups[1].replace("]", "");
+                let [p1, p2] = m.split("["); p2 = p2.replace("]", "");
                 mask = mask.replace(new RegExp(`${escapeRegex(p1)}\\[${escapeRegex(p2)}\\]`),
                     p1.charAt(0) === p2.charAt(0) ?
                         `(${p1}|${p1}${p2})` :