Using Ionic 2 can we build both hybrid and progressive web app?

I am using ionic 2 CLI and I have generated a new project using their CLI.

Inside the WWW folder two files are generated which really confused me. Files are manifest.json for web app install and serviceworker.js.

From here I got a doubt, with the ionic 2 can we build both with same codebase. I am newbie to Ionic.

Can we use the WWW folder for webapp deploy?