Mocha supports third-party reporters that can support advanced or specific use-cases. A reporter wraps around a Runner object and optionally listens to the events it emits.
To use a reporter published on npm (e.g., lcov-reporter), install it locally and set --reporter lcov-reporter. Alternatively, you can set the reporter in .mocharc.json as we've done here.
It is a very similar setup for third party UI's.
For more details, including a list of which argument types go with which runner event, see Tutorial: Create a Custom Reporter.
npm test- run our tests using the local.mocharc.jsonconfig file. They are run from the default location (/test) with the reporter found insrc/my-reporter.js.