I'm already planning for quite some time to practice to code with assertions to later use unassert to get rid of them.

Currently I imagine, that in an ideal scenario, i want to remove all uses assert but maybe not the ones that are exposes as an API to users. Given valid inputs to whatever the API is, all internal libraries should work correctly, because of assert, but given incorrect API inputs, things might break when asserts are removed.
But then again - even if only a single assert remains, it will pull in assert as a dependency, which is not really desirable when using the result in the browser.

Is that correct?

Can you recommend some tutorials/howtos and/or nice examples how to get started?