As I’ve mentioned before, I’m in the middle of putting together a React reference app and I’m doing it using Test Driven Development. The problem is, the standard tools for implementing ES2015 code coverage with Jest make it hard to see at a glance if you have 100% code coverage or not because of some issues with the way Jest tells Babel to do the transformations by default, the way Babel transforms the code and implements the auxiliaryCommentBefore option and the way that Istanbul parses the ignore next comments.
I’ve been working on solving this problem for the last month and a half off and on. I’ve even posted a question about this on Stack Overflow, so I’m pretty sure no one else has a solution for this yet. I’m not going to say my solution is the best way to solve this problem, but it is a solution, which is better than what we have so far.