Docker error: no such file or directory, open '/package.json'

My silly mistake was that I had forgotten to specify my WORKDIR before attempting to run my npm commands... Hope this helps someone too! Be sure to make sure your WORKDIR is accurate for the CMD line...

When npm install command is run, the working directory is probably /, and there is no package.json here.

Just uncomment your line WORKDIR /home/app/ in your Dockerfile.