What is the proper way to get a session parameters (like username of currently logged user) in Polymer UI.
I've expected something like:
Your login: [[msg('session$userLogin')]]
but not works
Currently there is no direct access to session params in Polymer UI. If you just need to display user login there is a special method in REST API.
Here is the example of a component which loads and displays user login: https://gist.github.com/web-devel/3659ef13ccaefc6597e1ae649dcb42cf
If you need to access other session params you can create a middleware service and make it available in REST API