Fixed Typo and added modularity

Fixed the lettemp typo and added modularity by determining the menu type on enable() rather than on initialization (i.e. in case noally is enabled prior to enabling presentation mode). I also added some comments.

presentationmode@ampad.de/extension.js

@@ -20,32 +20,36 @@ const SessionIface = {
 };
 let SessionProxy = DBus.makeProxyClass(SessionIface);
 
-// Put your extension initialization code here
+// Initialization code here:
 function init(extensionMeta) {
- // To Avoid issues and glitching, this needs to be placed here as
- // batteryMenu must be constant after initialization to avoid
- // problems with enable and disable functions
-
+ //Default Value on batteryMenu, it maybe changed on enable()
  batteryMenu = Main.panel._statusArea.battery;
+
+ imports.gettext.bindtextdomain("gnome-shell-extension-presentationmode",
+ extensionMeta.path + "/locale");
+ imports.gettext.textdomain("gnome-shell-extension-presentationmode");
+}
+
+function enable() {
+ //Temporary variable to check power devices
  let temp = Main.panel._statusArea.battery._deviceItems;
  if(temp == "")
- {//check for no battery or power device, i.e. no power menu
- lettemp = new Main.Panel.STANDARD_STATUS_AREA_SHELL_IMPLEMENTATION["a11y"]
+ { //check for no battery or power device, i.e. no battery menu
+ let temp = new Main.Panel.STANDARD_STATUS_AREA_SHELL_IMPLEMENTATION["a11y"]
  if(Main.panel._statusArea.a11y != null)
- {//check for no a11y (such as from noa11y extension)
+ { //check for no a11y (such as from noa11y extension)
  batteryMenu = Main.panel._statusArea.a11y;
  }
  else
- {//else use the user menu
+ { //else wise, resort to using the user menu
  batteryMenu = Main.panel._statusArea.userMenu;
  }
  }
- imports.gettext.bindtextdomain("gnome-shell-extension-presentationmode",
- extensionMeta.path + "/locale");
- imports.gettext.textdomain("gnome-shell-extension-presentationmode");
-}
-
-function enable() {
+ else
+ { //If all else is good, the battery menu is fine
+ batteryMenu = Main.panel._statusArea.battery;
+ }
+ //Add the Presentation mode Option
  batteryMenu._itemSeparator = new PopupMenu.PopupSeparatorMenuItem();
  batteryMenu.menu.addMenuItem(batteryMenu._itemSeparator);
  batteryMenu._presentationswitch = new PopupMenu.PopupSwitchMenuItem(_("Presentation mode"), false);