Option to exit dev server on build errors?

[dallonf]

We currently run our integration test suite (via Cypress) against the dev server (react-scripts start). start-server-and-test is very handy for starting the server, waiting for it to listen on a port, and then shut down the server after tests are run.

However, if there's an error that prevents the app from building (ex: a missing dependency), it has to get all the way through the integration test suite, running every test and failing them due to the build error thrown by Webpack. These builds would fail much faster if the dev server actually immediately quit with exit code 1 if there was a build error.

Would it be reasonable to have this behavior if CI=true? I'll happily write the PR, just want to check on my approach before I sink any time into it.

[Timer]

Hmm; this seems reasonable. To clarify, the dev server will only exit with build error on first invoke, not reloads?

[dallonf]

That's... uh, a good question, actually, I hadn't considered it. What would you prefer?

[Timer]

Truth be told, I'm not sure what'd be most valuable. Probably only the first load, not reloads?

[dallonf]

Actually, after some tinkering, I've decided what would be a more valuable option is the ability to build what you would see in the "dev" server as static files you can host the same way as a production build. The normal build script isn't ideal for the CI use case because it's so much slower.