This tutorial uses the same application that the Build a Node.js and React app with npm tutorial is based on. Therefore, you'll be building and testing the same application but this time, its delivery will be different depending on the Git branch that Jenkins builds from. That is, the branch being built determines which delivery stage of your Pipeline is executed.
jenkins directory contains an example of the
Jenkinsfile (i.e. Pipeline)
you'll be creating yourself during the tutorial and the
contains shell scripts with commands that are executed when Jenkins processes
either the "Deliver for development" or "Deploy for production" stages of your
Pipeline (depending on the branch that Jenkins builds from).