npm fails with missing dependencies

[ghost]

I wanted to give jupyterlab_json a try to display JSON in a notebook. "pip install jupyterlab_json" as not work, as there is no released package on Pypi. I cloned the repo and did a "pip install .", which fails with various errors like:

Module build failed: ReferenceError: Unknown plugin "transform-es3-property-literals"

I installed a few of them manually using npm, but always run into the next error about missing plugins. So it looks like something is broken. I'm not too much into this npm stuff, so I don't know exactly what to look for, but I'm happy to help, if you tell me which infos you would need.