npm install -g jscov
jscov --help on the command line and the rest should be obvious.
You can also use it programmatically. It has two functions and can be used like this:
Pull request are welcome obviously!
Running the tests requires jscoverage to be installed. This is because the main part of the tests compares the output of jscov to jscoverage. Get it here http://siliconforks.com/jscoverage or do what
.travis.yml does to get it up and running.