You'll need node / npm installed. To get up and running just enter:
# Download the npm packages you need (including the type definitions from DefinitelyTyped)
yarn install
# Compile the code and serve it up at http://localhost:8080
yarn start
# If you'd like to run your tests in watch mode then fire up a separate console and enter this command:
yarn test:watch
When you're building for production then yarn build
. To run tests in CI then yarn test