Request: 'istanbul instrument' should optionally create a 'baseline' coverage*.json file

[nwwells]

We're adding coverage to an existing project, and many files are not covered. Since the coverage json generated from the instrumented code essentially reports 'undefined' for files that weren't touched during the testing, our coverage stats are inaccurate (i.e. way too high).

My proposal is to provide an option in the instrument CLI to generate a 'coverage-baseline.json' file for the files instrumented, such that if you ran a report on the generated file, you'd see all the files, with 0% coverage.

[gotwarlost]

This is a good idea. Let me look into the easiest way of adding this.

[gotwarlost]

Darn it - used the wrong issue id in the commit message.

The following commit adds this feature:

092f336

[gotwarlost]

OK, version v0.1.23 adds this feature. Let me know if it works as expected for you.

@davglass FYI, in case it is useful for you guys too.

[nwwells]

Thanks, this works for us!