What is the easiest way to identify unused javascript code?

Question

JavaScript

The bottom line is this: there is a js application, a lot of files with scripts, there is a namespace (functions are declared both inside the namespace and separately).
After a major refactoring, I would like to know which of the declared functions are not used (and which of the callables are not declared) - what is the easiest way to do this?

Answer 1

Pass through istanbul and X% of users issue modified code, after every YY seconds, dump `window.__coverage__` to the server.

Result Example

Answer 2

I can advise you to run the project through the analyzer in JetBrains products (WebStorm, PhpStorm, etc.)
I have never seen better