ESLint v9 Support? (flat config)

[timble-one]

Compatibility Problem? - TypeError: Error while loading rule 'relay/no-future-added-value': Rule must be an object with a create method

eslint.config.js

export default [
  ...tseslint.config(
    { ignores: ['dist'] },
    {
      files: ['**/*.{ts,tsx}'],
      languageOptions: {
        ecmaVersion: 2020,
        globals: globals.browser,
      },
      extends: [js.configs.recommended, ...tseslint.configs.recommended, relay.configs.recommended],
      rules: {
        ...reactHooks.configs.recommended.rules,
        ...reactRefresh.configs.recommended.rules,
        'react-refresh/only-export-components': [
          'warn',
          { allowConstantExport: true },
        ],
        'react-hooks/exhaustive-deps': 'off',
      },
      plugins: {
        'react-hooks': reactHooks,
        'react-refresh': reactRefresh,
        relay
      },
    },
  ),
]

Error

Oops! Something went wrong! :(

ESLint: 9.20.0

TypeError: Error while loading rule 'relay/no-future-added-value': Rule must be an object with a `create` method
Occurred while linting /Users/timo/projects/flexirent/flexirent-frontend/src/app/pages/Page.tsx
    at createRuleListeners (/Users/timo/projects/flexirent/flexirent-frontend/node_modules/eslint/lib/linter/linter.js:1002:15)
    at /Users/timo/projects/flexirent/flexirent-frontend/node_modules/eslint/lib/linter/linter.js:1144:84
    at Array.forEach (<anonymous>)
    at runRules (/Users/timo/projects/flexirent/flexirent-frontend/node_modules/eslint/lib/linter/linter.js:1075:34)
    at #flatVerifyWithoutProcessors (/Users/timo/projects/flexirent/flexirent-frontend/node_modules/eslint/lib/linter/linter.js:2001:31)
    at Linter._verifyWithFlatConfigArrayAndWithoutProcessors (/Users/timo/projects/flexirent/flexirent-frontend/node_modules/eslint/lib/linter/linter.js:2083:49)
    at Linter._verifyWithFlatConfigArray (/Users/timo/projects/flexirent/flexirent-frontend/node_modules/eslint/lib/linter/linter.js:2172:21)
    at Linter.verify (/Users/timo/projects/flexirent/flexirent-frontend/node_modules/eslint/lib/linter/linter.js:1626:61)
    at Linter.verifyAndFix (/Users/timo/projects/flexirent/flexirent-frontend/node_modules/eslint/lib/linter/linter.js:2410:29)
    at verifyText (/Users/timo/projects/flexirent/flexirent-frontend/node_modules/eslint/lib/eslint/eslint.js:327:48)

Workaround

First i tried to disable this rule (relay/no-future-added-value) but it looks like all of the rules cause this error.

I also tried to use the compability-library from eslint: https://github.com/eslint/eslintrc#usage
Doesn't solve the problem neither.

I downgraded eslint to v8.5 and backported eslint.config.js to .eslintrc.cjs
But because eslint v8 is end of live this is not really satisfying.

Import Problem (solved) - TypeError: relay.configs.recommended is not iterable

it looks like this plugin does not yet support the new flat config system introduced in ESLint v9.

If i do this:

export default tseslint.config(
  { ignores: ['dist'] },
  {
    extends: [
      js.configs.recommended,
      ...tseslint.configs.recommended,
      ...relay.configs.recommended
    ],

I get this:

TypeError: relay.configs.recommended is not iterable

Solution for Import Problem

This was a stupid mistake of mine.

If i import it like this, this works: import relay from 'eslint-plugin-relay'