# use-services Requires the use of `Services` rather than `Cc[].getService()` where a service is already defined in `Services`. ## Examples of incorrect code for this rule ```js Cc["@mozilla.org/appshell/window-mediator;1"].getService(Ci.nsIWindowMediator); Components.classes["@mozilla.org/toolkit/app-startup;1"].getService(Components.interfaces.nsIAppStartup); ``` ## Examples of correct code for this rule ```js Services.wm.addListener() Cc["@mozilla.org/uuid-generator;1"].getService(Ci.nsIUUIDGenerator) ```