Despite Babel configuration, Babel not being used

[hyperupcall]

Describe the bug

While working on #879, I noticed that we have Babel installed, but do not use it. I explain how so below. In #879, I simply removed Babel to resolve this - if we aren't using it, and there are no issues, then maybe it should be good to remove?

But thinking about, I wanted to ask to be sure. For example, FormatJS has a Babel transform that purports to reduce the bundle size. If we remove Babel, then this can no longer be used.

Increasingly, like Webpack, people are moving away from Babel. Most supported browsers by web apps are evergreen browsers, and update quickly to support the latest features. In addition, TypeScript has options that will cause a compilation fail if modern features are used (say library methods from ES2023). If we remove Babel, that will make the compilation pipeline easier to understand, and we can still make sure develoeprs only use features supported by all modern browsers by configuring TypeScript.

Thoughts?

Expected behavior

To run babel-loader on our JavaScript files.

To Reproduce

We can see what loaders are being ran through a command line flag:

$ ./node_modules/.bin/webpack build --color --progress --mode development --profile --json=compilation-stats.json

Reading compilation-stats.json, Ctrl+f'ing for ts-loader, I read 657 instances such as:

...
	"issuerPath": [
		{
			"identifier": "/storage/ur/storage_home/Docs/Programming/Repositories/fox-forks/OED/node_modules/ts-loader/index.js!/storage/ur/storage_home/Docs/Programming/Repositories/fox-forks/OED/src/client/app/index.tsx",
			"name": "./src/client/app/index.tsx",
			...

But, no results show for babel-loader.

Looking at the webpack.config.js, the issue becomes apparent after reading the line:

{ test: /\/jsx?$/, exclude: /node_modules/, use:[{loader: 'babel-loader'}] }

The test regex matches no files, because it only runs on paths that end with /jsx. Even if that were fixed, there is only 1 JavaScript file (src/client/app/translations/data.js). This means that we will also have to configure babel-loader to be used after ts-loader, which looks something like:

{ test: /\.[jt]sx?$/, exclude: /node_modules/, use: ['babel-loader', 'ts-loader'] },