If your app already works with key storage extensions (nip-07, window.nostr) then you can use nostr-login library - two lines of code and all your calls to window.nostr are proxied to nip46 remote signing, with a pretty UI showing up for users to login/signup. 

 Yes I do the window.nostr(event) now. 

this one? https://www.npmjs.com/package/nostr-login
there's a github?   

 Yes
https://github.com/nostrband/nostr-login