Add environment variable DISABLE_ESLINT

[giuband]

The idea behind this new environment DISABLE_ESLINT_DEV variable is to:

1. speed up compilation time on dev mode
2. allow developers to write temporary code without caring about ESLint too much.

At the moment 2) is pretty hard, because depending on your ESLint config you might not even able to have a console.log or an unused variable in your code without seeing your dev build failing, making the experience pretty frustrating.

Open for feedback. I am actually uncertain whether we should have instead just a DISABLE_ESLINT setting that would disable ESLint for both environments.

Related issues:

• Proposal: Option to build without linting #7828
• Speed up build by disabling lint #7078

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[giuband]

I've changed it to DISABLE_ESLINT as it would make this more useful for all the projects that already have a lint step in CI and/or precommit hooks, so to avoid duplicated linting.

[stale]

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[giuband]

Hi team, any updates on this one?

[mrmckeb]

I think this will likely be a config flag, we've been talking about adding a config file in the next major release of CRA. Does anyone else in the team have thoughts? @ianmcnally or @ianschmitz perhaps?

[michaelsbradleyjr]

Just my 2¢, but I think it would be awesome if a CRA project could have a cra.config.js file at the top-level of the project that worked similarly to next.config.js, i.e. CRA's config could be passed to a function-export from cra.config.js and tweaked as needed.

[mrmckeb]

@michaelsbradleyjr That's on the cards for v4 at this stage.

[Bessonov]

I don't care about CRAs eslint rules for two reasons. First one, I have own rule set, which I use through multiple projects. And the second, I don't want that eslint slows me down while development. Therefore a big +1 for this PR.

[stale]

This pull request has been automatically marked as stale because it has not had any recent activity. It will be closed in 5 days if no further activity occurs.

[Bessonov]

further activity occurs

[battaglr]

Thanks, @giuband! This is a great thing to have supported natively, since it's so frustrating having the build break on you while you're actively coding, so now you have to stop, add a disable comment, etc. It just breaks the flow.

Please, let me know if I can be of any help!

[AbraaoAlves]

It's very useful for this issue: #8096

[tomasbruckner]

any update on this?

[giuband]

@mrmckeb@ianmcnally any updates on this one? Is it still under the radar to offer more flexibility regarding running or not eslint?

[giuband]

Closing as this has been implemented in #10170. Thanks @mrmckeb !