Doing my tests with Ava github.com/sindresorhus/ava
hashnode.com/post/what-is-the-best-javascript-uni…
I don't do code coverage at all. Code coverage forces me to focus on wrong targets.
It doesn't say 'the code is covered by X trustworthy tests'. Nor does it say 'the same code is checked by Y different trustworthy tests'. It also doesn't say where are the weak points in my code, most likely to break.
IMO not all code in a project needs to be tested because not all code in my projects is relevant for users. Instead, I'll write tests, when things break. And things break already while developing. Just say'in I have many tests, but only for things which broke at some point in time.