jlpm run watch fails, yarn-run-all not found

[jdmansour]

Hi, I'm trying to set up a development environment as described in the readme, but the following command fails:

$ jlpm run watch
yarn run v1.21.1
$ yarn-run-all -p watch:*
/bin/sh: yarn-run-all: command not found
error Command failed with exit code 127.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

It seems there is no yarn-run-all command, which is hardcoded in package.json. I tried to find yarn-run-all, but the corresponding npm package is just an alias for npm-run-all. Is there anything else I have to install, or did some dependency change here?

[danlester]

I haven't tried running these commands myself recently but my guess is that something has changed in the latest version of JupyterLab. jlpm is one of their commands so perhaps take a look at their latest guidance on how to develop extensions - it's possible they don't even use jlpm anymore - it was really just a version of yarn (or maybe it was npm) bundled into JupyterLab. This was to avoid regular users having to install yarn/npm separately - behind the scenes JupyterLab had to build extensions regularly, every time a new one was installed, so they really needed yarn/npm to be an internal tool. However, they have improved things so that JupyterLab doesn't need to run this all the time any more.

If you find anything, please let us know!