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How to switch to the version with fast TypeScript compilation?

See original GitHub issue

Both #5903 and #6406 got silenced and from the last comment in the latter it looks like the work on async TypeScript compilation has been completed, but I don’t know how to tell if I am running the fast version already. My current CRA+TS setup is certainly not fast.

Is it enough to update react-scripts? To what version? Do I need to update the whole or create-react-app when wanting to create a new project with fast TypeScript compilation? What about an existing project? How do I update that to have fast TypeScript compilation?

I am using react-scripts v2.1.5 on a very shitty machine and compilation takes forever. Is it fast yer and am I to blame the machine or am I not fast yet and should I pursue updating?

For me, npm start from issuing the command to seeing Compiled successfully! takes two minutes and 20 seconds. The machine is an i7-3667U 2 GHz CPU with 8 GB of RAM. skipLibCheck is set to true. Not exactly a beast, but the project I am compiling is very small, I don’t believe it should take two and a half minutes for it to compile.

Issue Analytics

State:
Created 5 years ago
Comments:5 (5 by maintainers)

Top GitHub Comments

1reaction

deftomatcommented, Mar 1, 2019

Cold starts are generally quite slow. I’m pretty sure that during the cold start (when you start npm start), TypeScript is not a bottleneck. Most of that time is probably Babel and Webpack itself.

As an example, npm start took 40 seconds on my machine and then the next rebuild caused by updated code took 3 seconds. When I applied changes from mentioned PRs, start took the same 40 seconds but rebuilds took less than a second.

So yes, starting the CRA is slow, but I must admit that I don’t need to restart the build process for the whole workday.

0reactions

TomasHubelbauercommented, Mar 1, 2019

@deftomat Is most of the slowness due to tsc itself then? I am really surprised to see how slow TS CRA is because on pure tsc projects I have never had a compilation run for more than thirty seconds and I am even stretching that. With the way CRA uses TS it is 5x as slow. Have I just been lucky to not find this with pure TS? I am completely blind to what WebPack, Babel etc. do on this front and how much overhead is due to them, that’s why I am curious.