Made the battery disappear if there's nothing to show

widgets/battery.lua

@@ -137,7 +137,7 @@ return function(args)
     end
     update_virtual_battery()
     -- Update loop
-    gears.timer({
+    local power_update = gears.timer({
         timeout = args.power_polling or 2,
         autostart = true,
         callback = function()
@@ -205,7 +205,7 @@ return function(args)
         end
     end
     -- Update loop
-    gears.timer({
+    local backlight_update = gears.timer({
         timeout = args.backlight_polling or 2,
         autostart = true,
         callback = function()
@@ -222,5 +222,11 @@ return function(args)
         end
     })
     -- }}}
+    -- We don't need this widget if we don't have anything to show
+    if #widget_map == 0 then
+        backlight_update:stop()
+        power_update:stop()
+        return 
+    end
     return battery_widget
 end