Jupyter labextension install fails on Mac

I was following the directions in JupyterLab Documentation, Managing Extensions with jupyter labextension.

“The Extension Manager in JupyterLab and the jupyter labextension install command can install source extension packages from npm.”

In Terminal: jupyter labextension install.
This results in: “An error occured.
ValueError: “/Users/markbarden” is not a valid npm package”

… rendering me completely confused.

Is this the doc you’re referring to? Extensions — JupyterLab 3.1.0rc2 documentation

You need to pass either the name of an extension on NPM, or the path to a local directory containing the source code for an extension e.g. if you’re developing one locally. What are you trying to do?