Typescript issue in flat config: Types of property 'parser' are incompatible

[silverwind]

Given the following flat config (in a shared config):

import importPlugin from "eslint-plugin-import-x";
import type {Linter} from "eslint";

export default [{
  plugins: {
    "import-x": importPlugin,
  },
}] satisfies Array<Linter.Config>;

I'm presented with the following boatload of a typescript error on line 6:

index.ts:6:5 - error TS2322: Type '{ configs: { recommended: { plugins: ["import-x"]; rules: { 'import-x/no-unresolved': "error"; 'import-x/named': "error"; 'import-x/namespace': "error"; 'import-x/default': "error"; 'import-x/export': "error"; 'import-x/no-named-as-default': "warn"; 'import-x/no-named-as-default-member': "warn"; 'import-x/no-duplica...' is not assignable to type 'Plugin'.
  Types of property 'configs' are incompatible.
    Type '{ recommended: { plugins: ["import-x"]; rules: { 'import-x/no-unresolved': "error"; 'import-x/named': "error"; 'import-x/namespace': "error"; 'import-x/default': "error"; 'import-x/export': "error"; 'import-x/no-named-as-default': "warn"; 'import-x/no-named-as-default-member': "warn"; 'import-x/no-duplicates': "warn...' is not assignable to type 'Record<string, LegacyConfig<RulesRecord, RulesRecord> | Config<RulesRecord> | Config<RulesRecord>[]>'.
      Property ''stage-0'' is incompatible with index signature.
        Type 'PluginConfig' is not assignable to type 'LegacyConfig<RulesRecord, RulesRecord> | Config<RulesRecord> | Config<RulesRecord>[]'.
          Type '{ plugins?: ["import-x"] | undefined; settings?: { "import-x/cache"?: { lifetime?: number | "∞" | "Infinity" | undefined; } | undefined; "import-x/core-modules"?: string[] | undefined; ... 9 more ...; "import-x/resolver-next"?: NewResolver[] | undefined; } | undefined; rules?: Record<...> | undefined; } & Config' is not assignable to type 'LegacyConfig<RulesRecord, RulesRecord> | Config<RulesRecord> | Config<RulesRecord>[]'.
            Type '{ plugins?: ["import-x"] | undefined; settings?: { "import-x/cache"?: { lifetime?: number | "∞" | "Infinity" | undefined; } | undefined; "import-x/core-modules"?: string[] | undefined; ... 9 more ...; "import-x/resolver-next"?: NewResolver[] | undefined; } | undefined; rules?: Record<...> | undefined; } & Config' is not assignable to type 'LegacyConfig<RulesRecord, RulesRecord>'.
              Types of property 'overrides' are incompatible.
                Type 'ConfigOverride[] | undefined' is not assignable to type 'ConfigOverride<RulesRecord>[] | undefined'.
                  Type 'ConfigOverride[]' is not assignable to type 'ConfigOverride<RulesRecord>[]'.
                    Type 'ConfigOverride' is not assignable to type 'ConfigOverride<RulesRecord>'.
                      Types of property 'parser' are incompatible.
                        Type 'string | null | undefined' is not assignable to type 'string | undefined'.
                          Type 'null' is not assignable to type 'string | undefined'.

Not sure how long this error is there, I'm still using eslintrc config, but am trying to finally migrate to flat.

[SukkaW]

@silverwind I can look into improving a few types of config presets.

[silverwind]

Thanks. The error probably went unnoticed so far because eslint configs are usually JS, not TS.

[SukkaW]

@silverwind So I have been looking into this. We have typed our rules with satisfies Record<string, TSESLint.RuleModule<string, readonly unknown[]>> (which is from typescript-eslint) which is conflicted with @types/eslint.

So I don't know what to do. if we make eslint-plugin-import-x compliant with @types/eslint, we will lose type information about the rule config. But if we stick with typescript-eslint, we can't use eslint-plugin-import-x with @types/eslint's types.

[silverwind]

Hmm, sounds like a bug in either typescript-eslint or @types/eslint, tbh.

[SukkaW]

Hmm, sounds like a bug in either typescript-eslint or @types/eslint, tbh.

Nah. It just happens that they both maintain their own types and are not compatible with each other. We use the types from typescript-eslint because we also use utilities from them.