How to get the userId of logged in partner user from community and use it in all the community pages?

I want to get the userId for the partner user who has logged in the community portal. Instead of sending the id of the user in the url for every page in community, is there any alternative approach by which I can store the id of the logged in partner user in a variable and use it globally in all the pages in community. 

#Community Cloud #Community Portal #Partner Community #Partner Community User #Analytics #Trailhead #New Releases #Integration #AppExchange