react-scripts 5 is fast!

[ggascoigne]

One thing that I've not seen much chatter about that I feel is worth pointing out if you are still on the fence about upgrading to cra-v5 from v4. The dev experience is way faster. We have about 250k lines of predominantly TypeScript code. These are the timings that we saw.

command	version	uncached	cached
yarn start	v5	143s	16s
	v4	181s	113s
yarn build	v5	387s	232s
	v4	409s	184s

The initial start after installing dependencies is a bit faster, but subsequent starts have gone from about 2 minutes to about 15s!

This is the single biggest cra performance improvement I've seen since I started using it several users ago, so a huge shoutout to all of the people who helped get this release out, it's a great win.

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Yes, there were some things that weren't completely obvious to sort out to get this working, but craco or patch package are your friend for now. There are a lot of good solutions listed in other discussion threads here, so yes, perhaps a bit of work, but the benefits are seriously worth it. I've upgraded three projects so far, two of them just worked, the third needed some small tweaks.