Helper functions I found useful
Work for both NodeJS and Browser
run npm run test
to execute unit test
See more https://www.codementor.io/davidtang/unit-testing-and-tdd-in-node-js-part-1-8t714s877
Use plugin to auto run https://marketplace.visualstudio.com/items?itemName=Orta.vscode-jest
See how https://gist.github.com/paambaati/54d33e409b4f7cf059cc
But I prefer run node test/index.js for easier