How can we prevent multiple log in for ionic 2 application

I am creating ionic 2 application with JWT authentication can you please give me suggestions how can we prevent multiple log in and what is best way to implement our own authentication in ionic 2 application (not third party jwt authentication ). I would be grateful for your suggestions. Thank you.

This doesn’t really seem to be anything specific to ionic 2, but rather general app auth. Have you asked on Stackoverflow, the general nature of this question might be a better fit there.