Add optional field to sharedPackages in package.json -> jupyterlab

[edublancas]

Problem

Currently, there is no way to mark javascript dependencies in package.json -> jupyterlab -> sharedPackages as optional.

Background:

I'm developing an extension that adds new functionality through toolbar buttons and widgets.

In an earlier release, I made ipywidgets a dependency because of the widgets. Now, I want to make ipywidgets an optional dependency, so I removed it from the pyproject.toml.

When testing the package, I realized that removing ipywidgets broke it, and upon debugging, I noticed that the error came because the extension could not find the @jupyter-widgets/base JS package. After some debugging, I noticed that my package.json has a jupyterlab section and a sharedPackages subsection (I created this project from the template).

It seems like since I no longer have ipywidgets as a dependency, @jupyter-widgets/base is never installed and the package breaks, because it's configured to share the @jupyter-widgets/base package (via sharedPackages)

For now, I eliminated ipywidgets from the sharedPackages section. This fixed the problem, but it isn't an ideal solution.

Proposed Solution

Add an optional field to sharedPackages in package.json -> jupyterlab to indicate that some dependency is optional.

Additional context

Jupyter forums question: https://discourse.jupyter.org/t/optional-dependency-for-jupyterlab-extension/21557

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[fcollonval]

Hey @edublancas

I think in your specific case, the sharedPackage is not the culprit but rather the way you specify the dependency between your widget plugin and the jupyter widget registry.

Specifically, that line:

requires: [IJupyterWidgetRegistry],

at https://github.com/ploomber/jupysql-plugin/blob/567fb10014fb0abbc0f993f1138657b111658774/src/widgets/index.ts#L17

should be

optional: [IJupyterWidgetRegistry],

Note: an optional token will be set to null if not provided. So you should test you got a token before registering your widget.

Then add back the entry in sharedPackages (bundled = false & singleton = true) and I think it will work.

[edublancas]

hi @fcollonval, thanks for your feedback! I'll try the approach you suggested and see how it goes.