IPyWidget renders Output Error creating widget: could not find model

[echarles]

Followup of https://github.com/datalayer-examples/jupyter-react-webpack-example/issues/1 opened by @zkbitcoin

IPyWidgets rendering with he Output component is failing with Error creating widget: could not find model - loading code directly in notebook works.

const SOURCE_IPYWIDGET = 'import ipywidgets as widgets
widgets.IntSlider(
value=7,
min=0,
max=10,
step=1
)'

Output
autoRun={true}
kernel={kernel}
code={SOURCE_IPYWIDGET}