Modularized top menu functionality into its own module

js/dom/setup/setup_top_menu.js

 const app = require('../../app');
 const Server = require('../../server');
 const Toast = require('../toast');
+const TopMenu = require('../top_menu');
 
 module.exports = () => {
 
@@ -31,20 +32,14 @@ module.exports = () => {
   const $btnNext  = $('#btn_next');
   const $btnDesc  = $('#btn_desc');
 
-  const flowControlBtns = [ $btnPause, $btnPrev, $btnNext ];
-
-  const setFlowControlState = (isDisabled) => {
-    flowControlBtns.forEach($btn => $btn.attr('disabled', isDisabled));
-  };
-
   // initially, control buttons are disabled
-  setFlowControlState(true);
+  TopMenu.disableFlowControl();
 
   $btnRun.click(() => {
     $btnTrace.click();
     $btnPause.removeClass('active');
     $btnRun.addClass('active');
-    setFlowControlState(false);
+    TopMenu.enableFlowControl();
     var err = app.getEditor().execute();
     if (err) {
       console.error(err);

js/dom/top_menu.js

+'use strict';
+
+const flowControlBtns = [ $('#btn_pause'), $('#btn_prev'), $('#btn_next') ];
+const setFlowControlState = (isDisabled) => {
+  flowControlBtns.forEach($btn => $btn.attr('disabled', isDisabled));
+};
+
+const enableFlowControl = () => {
+  setFlowControlState(false);
+};
+
+const disableFlowControl = () => {
+  setFlowControlState(true);
+};
+
+const resetTopMenuButtons = () => {
+  $('.top-menu-buttons button').removeClass('active');
+  disableFlowControl();
+};
+
+module.exports = {
+  enableFlowControl,
+  disableFlowControl,
+  resetTopMenuButtons
+};

js/tracer_manager/manager.js

 'use strict';
 
+const TopMenu = require('../dom/top_menu');
+
 const stepLimit = 1e6;
 
 const TracerManager = function () {
@@ -180,7 +182,7 @@ TracerManager.prototype = {
 
     this.timer = setTimeout(() => {
       if (!tracer.nextStep(options)) {
-        $('#btn_run').removeClass('active');
+        TopMenu.resetTopMenuButtons();
       }
     }, this.interval);
   },
@@ -242,4 +244,4 @@ TracerManager.prototype = {
   }
 };
 
-module.exports = TracerManager;
\ No newline at end of file
+module.exports = TracerManager;