When installing new jupyterlab extensions or widgets, a common error displayed is:
Error displaying widget: model not found.
The console displayed cryptic error messages such as:
Could not instantiate widget, Error: Could not create a model., Module @jupyter-widgets/base, semver range ^2.0.0 is not registered as a widget module.
The solution proposed is generally "uninstall and re-install".
I would like to know
- How to actually debug this error?
- What does "model not found" mean?
- Where is Jupyter looking for the model?
- What is a "semver-range" and how can I see what exactly was not registered as a widget module?
- Can a user do something to "register the model"?
- Can we get Jupyter or JS to display what folders it is looking for information and where they are configured?
This error is so common with a large number of widgets that it would be helpful to show people what it actually means and how to investigate it.