jupytext port build cannot find jlpm

[Jonathan Stickel]

I'm trying to update the port `py-jupytext` since the recent updates to 
Jupyterlab. The jupytext package now uses node.js and jlpm to build. The 
port `py-jupyterlab` provides jlpm, but it is in the path as 
`jlpm-{python.branch}`, and consequently jupytext cannot find it. I 
tried patching `${worksrcpath}/pyproject.toml` to have

npm = ["jlpm-${python.branch}"]

This is similar to the Portfile for py-notebook. It helps get past the 
first use of jlpm, but a later step fails:

command not found: jlpm

Recommendations for how to resolve this issue? Is there a way to set an 
alias during the build phase?

alias jlpm="jlpm-${python.branch}"

Or add 
"${prefix}/Library/Frameworks/Python.framework/Versions/${python.branch}/bin" 
to the path? I haven't been successful implementing either approach.

Thanks,
Jonathan

P.S.
I've been wondering if it is worth the trouble to create and maintain 
ports for some of these python packages. These days they are often using 
advanced python-internal build tools that are difficult to configure, 
while `pip install <package>` often just works. By comparison, there is 
a port for Julia but none of its packages, instead relying entirely on 
Julia's package manager. I'm curious about the thoughts of others on 
this matter.