I usually trigger a service on my backend that gets a username and password. This service validates and returns a JWT token.
At angular, I use the $ localStorage provider to store it. For each request that will be made to my API, I look for the token stored in the login and include it in the request HEADERS to validate it in the backend.
If you want to use the non-angular token for any purpose, you can use angular-jwt to decode it with the jwtHelper.decodeToken (token) function; and / or validate through the jwtHelper.isTokenExpired (token) function
Oh, to use this angle-jwt you need to add it in the module of your app ('angular-jwt').