Upgrade Webpack

[rfultz]

We should look into upgrading Webpack.

When upgrading Node and the testing packages, I found that upgrading to the latest webpack (4) caused our bundling to break. A little research led me to a dependency that didn't like how we were using CommonsChunkPlugin (and how it would transition to the SplitChunksPlugin, since CommonsChunkPlugin is deprecated in webpack 4) and that it'll be fixed in a forthcoming release.

Remember: watch webpack plugin releases.
Option: re-evaluate how we're using Webpack?

Followup work:

• Re-review homepage for optimization. Old ticket: Homepage Optimization - CLS #5015

[rfultz]

@patphongs, I'm increasing the priority here. The security issue with tar's version #2821 has been solved for node-gyp@4 but not for our node-gyp@3.8.0 (yet). I'd like not to postpone the Webpack upgrade until there's a pressing security issue and we have to rush to upgrade.

[rfultz]

Upgrading Webpack should make our site load faster, too. Google may be looking at that soon: https://www.engadget.com/2019/11/11/chrome-slow-loading-websites-speed-badging-label/

[rfultz]

We've waited long enough that Webpack 5 is under construction (probably 65% there, by their Git milestone). No current release date announced. It's still in beta and there are several other packages who only support Webpack 5 with their beta versions.

[rfultz]

Researched this week and got the structure of our current build transitioned to Webpack 4.
Next problems to solve:

• dev build takes > 38s
• prod build takes > 500s
• exported files are larger than from Webpack 4

Next steps:

• Enable dev hotswap (replacing npm watch, I suspect)
• Work with SplitChunks and CDN