Odd 'loose' mode configuration must be the same...

'loose' mode configuration must be the same for both @babel/plugin-proposal-class-properties and @babel/plugin-proposal-private-methods

I’m getting this error even though I don’t use either of the proposals explicitly. Thus, it’s kinda hard for me to configure their loose modes 😆 I think they are brought in through a preset.

My config is:

  "babel": {
    "plugins": [
      "babel-plugin-macros"
    ],
    "presets": [
      [
        "@babel/preset-env",
        {
          "useBuiltIns": false,
          "shippedProposals": true,
          "debug": false
        }
      ]
    ]
  },
  "babelMacros": {
    "styledComponents": {
      "pure": true
    }
  },

I’ve recently done yarn upgrade and this error showed up. Summary of babel versions that got upgraded in yarn.lock:

• 7.9.6 → 7.10.0: core, runtime, compat-data, generator, helpers, parser, traverse, types, helper-compilation-targets, helper-create-class-features-plugin, helper-replace-supers, …
• 7.8.6 → 7.10.0: template
• 7.8.3 → 7.10.0: helper-member-expressions-to-function, plugin-transform-spread
• 7.9.0 → 7.10.0: plugin-transform-for-of
• …

[danielbayerlein]

I have the same problem with Storybook (v6.0.0-beta.15).

[c-frater]

After a lot of debugging, we found that simply adding the plugins (without options) seems to work.

plugins: [
      '@babel/plugin-proposal-class-properties',
      '@babel/plugin-proposal-private-methods',
    ],

We don’t use the plugins directly in our app but it seems they’re included in env. Without them listed in plugins it fails, listing them with loose: true also fails so I can only assume that the ‘default’ doesn’t trigger the warning

I’ll try and upload the lockfile with the business-sensitive bits removed later today