Babel 7.13 compiler assumptions

[hyperknot]

Hi, will it be possible to use the Babel 7.13 compiler assumptions with an assumptions key? https://babeljs.io/docs/en/assumptions

For example MobX docs say the following:

{
    "plugins": [["@babel/plugin-proposal-class-properties", { "loose": false }]],
    // Babel >= 7.13.0 (https://babeljs.io/docs/en/assumptions)
    "assumptions": {
        "setPublicClassFields": false
    }
}

It'd be nice to use this syntax in CRACO.

[DronDima]

Hello, i also have issue with assumptions. I'm trying to use decorator inside react class component, but babel overrides it. So, from different sources(one, two and others) it looks like i need to add @babel/plugin-proposal-decorators with legacy: true. But In official documentation they have note that we need to add setPublicClassFields assumption in babel config when using legacy: true.

[hyperknot]

@DronDima I don't think the assumption is needed as of today, as the current Babel is 7.12 in CRA.

This works for decorators:

module.exports = {
  babel: {
    plugins: [
      ['@babel/plugin-proposal-decorators', { legacy: true }],
      ['@babel/plugin-proposal-class-properties', { loose: false }],
    ]
  },
}

[hyperknot]

OK, the new CRA 5.x actually ships Babel 7.16, so we'd need these assumptions. Has anyone managed to get this right?

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[hyperknot]

Not stale

On 2022. May 1., Sun at 0:29, stale[bot] @.***> wrote:

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

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[dilanx]

@hyperknot sorry for such a long delay. I've added this functionality and will release it in alpha 8. I haven't tested it, but if you'd like to ensure that it works for you as you expect once alpha 8 is out, that would be great!

[hyperknot]

I've done the upgrade to test this. It seems to be working, at least I get a warning message if I add assumptions. There are other errors with react-scripts@5.x which I won't start debugging, but the CRACO part seems to be working.

[dilanx]

Thanks @hyperknot. If the craco part seems to be working, I'll close this issue. Feel free to leave a comment if there are any problems.