We recommend using nvm (Node Version Manager) or Docker to ensure that the versions of Node.js and npm are the same across development, Travis CI, staging, and production environments.
After installing nvm, to install both Node.js and npm run from the top of the git repo:
$ nvm install # Reads from .nvmrc
$ npm install -g npm@5.2.0 # Make sure this matches .travis.yml
To install the dependencies, from the top directory run
npm install
To build the bundled script with webpack run
npm run build
And to run the dev server, run
npm run dev