As per angular documentation, I understand that the production keys can be places in the "environment.prod.ts". However, what is not very clear to me is when during the build stage are:
- Does the variables being included in the final build? If yes, wouldn't this make the env variables exposed to the public which were supposed to be a secret? 
- If the variables included in the build, what is the correct way to deploy a production version of the application? (Let's say the app will be hosted on firebase) 
Thank you :)
 
    