python - How to get ipywidgets working in Jupyter Lab?

Question

In Jupyter Notebook, ipywidgets work fine, however they seem to not work in Jupyter Lab (which is supposedly better than Notebook).

I followed these directions.

Step 1: Installed Node.js (https://nodejs.org/en/)

Step 2: Installed requirements on Python 3 with conda:

conda install -c conda-forge ipywidgets
jupyter labextension install @jupyter-widgets/jupyterlab-manager

Unfortunately, basic widgets do not work inside the jupyter lab notebook:

Answer 1

JupyterLab now prefers a model where arbitrary javascript is no longer allowed to be embedded in a cell's output, which is how many interactive Jupyter Notebook modules used to work. They now ask that modules with interactivity create a JupyterLab extension. ipywidgets provides @jupyter-widgets/jupyterlab-manager extension which satisfies this requirement.

When using ipywidgets 7.6 or newer in JupyterLab 3.0 or newer you do not need to do anything: it is installed by default. You can check if this is installed by running:

jupyter labextension list

which should include a line like:

@jupyter-widgets/jupyterlab-manager v3.0.0 enabled OK (python, jupyterlab_widgets)

If you are using JupyterLab 1 or 2 (or old version of ipywidgets) you need to install this extension manually by running this on your command line (which assumes you already have NodeJS installed):

jupyter labextension install @jupyter-widgets/jupyterlab-manager