Switch webpack back to babel-loader

[rgbkrk]

As noted in https://github.com/gaearon/react-hot-loader/blob/master/README.md#typescript, in order to use react-hot-loader we have to use the babel-loader.

As of version 4, React Hot Loader requires you to pass your code through Babel to transform it so that it can be hot-reloaded.

During the conversion process to TypeScript I thought that in order for us to have type checking, I thought we'd have to switch over to ts-loader (for the sake of handling project references). It seems that we can set things up in a dual mode: type checking gets done with a rigorous tsconfig that uses project references while our webpack setup is allowed to use babel-loader + react-hot-loader.

[lgeiger]

Would switching back to babel would reintroduce #3594 due to babel/babel#8361?

There's a discussion on the next.js repo about this problem related to HMR: vercel/next-plugins#306

[rgbkrk]

We took the next.js apps out of the repo, so we won't run into that anymore. They'll use the transpiled packages.

[stale]

This issue hasn't had any activity on it in the last 90 days. Unfortunately we don't get around to dealing with every issue that is opened. Instead of leaving issues open we're seeking to be transparent by closing issues that aren't being prioritized. If no other activity happens on this issue in one week, it will be closed.
It's more than likely that just by me posting about this, the maintainers will take a closer look at these long forgotten issues to help evaluate what to do next.
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[captainsafia]

We'll still need to do this.

The work to introduce babel-loader has been introduced to our test workflows during the addition of ipywidgets support. We'll need to follow this through to the source code.

[stale]

This issue hasn't had any activity on it in the last 90 days. Unfortunately we don't get around to dealing with every issue that is opened. Instead of leaving issues open we're seeking to be transparent by closing issues that aren't being prioritized. If no other activity happens on this issue in one week, it will be closed.
It's more than likely that just by me posting about this, the maintainers will take a closer look at these long forgotten issues to help evaluate what to do next.
If you would like to see this issue get prioritized over others, there are multiple avenues 🗓:

• Ask how you can help with this issue 👩🏿‍💻👨🏻‍💻
• Help solve other issues the team is currently working on 👨🏾‍💻👩🏼‍💻
• Donate to nteract so we can support developers to work on these features and bugs more regularly 💰🕐

Thank you!

[captainsafia]

Closing this since we'll realistically not be able to handle this any time soon.