This is an example alongside my blog post DIY node_modules cache for Docker in your CI.
For testing purposes, you will first need to build the cache image, you can do so with the following command:
docker build . -f Dockerfile.cache -t node-cache.
Once done, you can build the main image, which will pull in the node-cache image with the following command:
docker build . -t docker-cache-example.
In order to run the image, simply run docker run -p 7010:7010 docker-cache-example.
You should then be able to see the vanilla CRA app running at localhost:7010.