You're right, When importing some of the modules from a library, You're "tree shaking" and your angular bundle won't include other -unconsumed- parts of that library.

In this article I gave 4 simple tips about how to ensure effective tree-shaking work in your app, But of course that are many more ways, Some more simple and some more advance, to maintain this state.

Maybe in the feature I'll write another pice dedicated only for tips.

Thanks for the comment :)