how to wite global services in angular js

i am writing the application for i-banking , how to use angular JS , as we have an idea about banking , left side main link under every main link 3 to 4 sub links will be there . how to write a common service every time whether the my login message is being available are not , how to verify , every time i will recieve json incase my session is not available i wills send common error code how to use across my all module , ex i have around 9 modules is there in my deskop application