[Bug]: rootMode: "upward" ignores local browserslist config

[AprilArcus]

💻

• Would you like to work on a fix?

How are you using Babel?

@babel/cli, babel-loader, babel-jest

Input code

See minimal repro at AprilArcus/rootmode-upward-with-browserslist-repro

Current and expected behavior

When invoking Babel with rootMode: "upward", local configs in .babelrc.js are respected, but the browserslist entry in package.json is not.

Expected behavior: browserslist should be read from the local package.json or .browserslistrc, and fall back to the root package.json or .browserslistrc if a local configuration is not found.

Environment

  System:
    OS: Linux 5.17 Debian GNU/Linux rodete 12 (rodete)
  Binaries:
    Node: 18.6.0 - /usr/bin/node
    npm: 8.15.1 - /usr/bin/npm

[babel-bot]

Hey @AprilArcus! We really appreciate you taking the time to report an issue. The collaborators on this project attempt to help as many people as possible, but we're a limited number of volunteers, so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack community that typically always has someone willing to help. You can sign-up here for an invite.

[nicolo-ribaudo]

For reference: .browserslistrc is supposed to be file-relative and not root/project-relative: babel/rfcs#2 (comment)

[AprilArcus]

I don't think I understand the comment you linked. It seems to me that a monorepo with multiple NPM workspaces in myRepo/apps/* should be able to target each app to a different set of supported browsers, and have that config live in a single location that can be read by e.g. both Webpack and Babel.

It would also be desirable for any workspaces destined to be published to NPM as packages to have an es5 or es2017 baseline target, configured separately from a bundled app that would target evergreen browsers.

[nicolo-ribaudo]

Yes, I agree with your expected behavior 👍 That was a comment from the browserslist author saying that different folders should be able to target different configs.