support multiple windows

assets/js/core/WakaTimeCore.js

@@ -89,7 +89,8 @@ class WakaTimeCore {
                 browser.idle.queryState(config.detectionIntervalInSeconds).then((newState) => {
                     if (newState === 'active') {
                         // Get current tab URL.
-                        browser.tabs.query({active: true}).then((tabs) => {
+                        browser.tabs.query({currentWindow: true, active: true}).then((tabs) => {
+                            if (tabs.length == 0) return;
 
                             var currentActiveTab = tabs[0];
                             var debug = false;

assets/js/events.js

@@ -39,6 +39,21 @@ browser.tabs.onActivated.addListener(function (activeInfo) {
 
 });
 
+/**
+ * Whenever a active window is changed it records a heartbeat with the active tab url.
+ */
+browser.windows.onFocusChanged.addListener(function (windowId) {
+
+    if (windowId != browser.windows.WINDOW_ID_NONE) {
+        console.log('recording a heartbeat - active window changed');
+
+        wakatime.recordHeartbeat();
+    } else {
+        console.log('lost focus');
+    }
+
+});
+
 /**
  * Whenever any tab is updated it checks if the updated tab is the tab that is
  * currently active and if it is, then it records a heartbeat.
@@ -47,7 +62,7 @@ browser.tabs.onUpdated.addListener(function (tabId, changeInfo, tab) {
 
     if (changeInfo.status === 'complete') {
         // Get current tab URL.
-        browser.tabs.query({active: true}).then(function(tabs) {
+        browser.tabs.query({currentWindow: true, active: true}).then(function(tabs) {
             // If tab updated is the same as active tab
             if (tabId == tabs[0].id) {
                 console.log('recording a heartbeat - tab updated');