Add command line option to turn off the outputReport

[gabrielschulhof]

Node.js: 12.4.0
c8: 5.0.1
Platform: Linux eagle 5.1.7-300.fc30.x86_64 #1 SMP Wed Jun 5 12:32:28 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

My test suite runs child processes and the decision as to whether to run them through c8 is passed along as a command line argument. The child processes output a JSON object which is parsed from their stdout to assert correctness. The unconditional production of c8's outputReport() interferes with the JSON.parse() of the child process' stdout.

Commenting out these lines is a workaround. It'd be nice if they could be turned off with a command line parameter.

[shinnn]

You can achieve essentially the same thing with the none reporter.

$ c8 node run.js
Hello
----------|----------|----------|----------|----------|-------------------|
File      |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files |      100 |      100 |      100 |      100 |                   |
 run.js   |      100 |      100 |      100 |      100 |                   |
----------|----------|----------|----------|----------|-------------------|

$ c8 --reporter=none node run.js
Hello

[gabrielschulhof]

@shinnn thank you!