load plotly.js from unminified dist bundle in plotlywidget

[jonmmease]

With this PR, both jupyterlab-plotly and plotlywidget now load plotly.js from the unminified dist bundle, so jupyterlab should be able to de-duplicate plotly.js when both extensions are installed.

Closes #1873

cc @vidartf

[emmanuelle]

So the index.js file is now larger (7 Mo instead of 4). Is this a problem (for other environments, eg Dash applications etc.). Probably a naive question :-)

[jonmmease]

@nicolaskruchten any thoughts on this. We could use the min bundle in both extensions instead of the regular one. My thinking was that this should be getting compressed everywhere it matters, but I don't have a strong opinion here.

[nrbgt]

Perhaps when making this change, please also consider registering the exports in the lab plugin with a lazy load: this will keep it from

• hitting the browser until it's actually requested
• getting compiled in with the already-titanic vendor~main

Here's how it interacts with the crucial loadClass: https://github.com/jupyter-widgets/ipywidgets/blob/master/packages/jupyterlab-manager/src/manager.ts#L383

Since it appears to be commonjs, you may have to use the vendor-specific webpack.ensure (or require.ensure?) rather than the standards-based await import. But doing it at the widget load level is far more convenient than trying to do it within the backbone-related code, which doesn't async much.

[nrbgt]

Here's an example with jupyter-threejs:

jupyter-widgets/pythreejs#297

[vidartf]

@nrbgt While I agree with your point, I believe it should be made as a separate issue.

[nrbgt]

@vidartf made issue #1913

[nicolaskruchten]

OK so as I understand it right now, this will bloat the nbextension size because we're not minifying in webpack.config.js.