In our recipe file we specify to pull node v.10.11.0 Alpine from a DockerHub base. The environment variables defined in %environment are needed for defining the dependencies (like in the case of YARN_VERSION) or for reference later in our Hello-world.js test script (below). Remember that these variables need to be defined in the %environment section to be exported. The %files section will copy the Hello-world.js we created before from the host to the container. The %startscript section will be run after starting an instance of our created container.
To test, we will need to define the contents of the Hello-world.js file. Use the editor of your choice. (ex. vim, emacs, nano) In this case we will use nano: