node-calculator · 
A simple app for automated tests using jest
How to run the app locally
To run locally you need to be sure that the dependencies are installed:
$ npm install
To run:
$ npm start
How to test the app
$ npm test
How to run code coverage
$ npm test -- --coverage
Note the duplicate --. The first separates the parameters passed to the npm command itself and the following are passed to the test script.