A journal written by @coffeencoke which includes notes on software development and product design.
https://github.com/GoogleChrome/big-rig https://github.com/GoogleChrome/big-rig/tree/master/test-runner https://developers.google.com/web/tools/chrome-devtools/profile/evaluate-performance/timeline-tool
Rather than code coverage, consider using something that mutates your code to see if the tests detect faults caused by the mutations.
PIT is a framework that does this for have projects: http://pitest.org