chore: Use eslint types for exported configs (#789)

This allows svelte configs to pass typescript-eslint type checking

Actually when migrating a project to eslint 9 I get typescript 2345
error
```ts
Argument of type '{ plugins: { readonly svelte: Plugin; }; files?: undefined; languageOptions?: undefined; rules?: undefined; processor?: undefined; } | { files: string[]; languageOptions: { parser: any; }; rules: { ...; }; processor: string; plugins?: undefined; } | { ...; }' is not assignable to parameter of type 'ConfigWithExtends'.
  Type '{ files: string[]; languageOptions: { parser: any; }; rules: { 'no-inner-declarations': string; 'no-self-assign': string; 'svelte/comment-directive': string; 'svelte/system': string; }; processor: string; plugins?: undefined; }' is not assignable to type 'ConfigWithExtends'.
    Types of property 'rules' are incompatible.
      Type '{ 'no-inner-declarations': string; 'no-self-assign': string; 'svelte/comment-directive': string; 'svelte/system': string; }' is not assignable to type 'Partial<Record<string, RuleEntry>>'.
        Property ''no-inner-declarations'' is incompatible with index signature.
          Type 'string' is not assignable to type 'RuleEntry | undefined'. ts(2345)
---
(property) 'flat/recommended': ({
    plugins: {
        readonly svelte: ESLint.Plugin;
    };
    files?: undefined;
    languageOptions?: undefined;
    rules?: undefined;
    processor?: undefined;
} | {
    files: string[];
    languageOptions: {
        parser: any;
    };
    rules: {
        ...;
    };
    processor: string;
    plugins?: undefined;
} | {
    ...;
})[]
```

Using const to define rule levels fixe the problem

Author: KuSh

.changeset/long-dingos-fold.md

@@ -0,0 +1,5 @@
+---
+'eslint-plugin-svelte': patch
+---
+
+chore: Use eslint types for exported configs

packages/eslint-plugin-svelte/src/configs/all.ts

@@ -1,8 +1,9 @@
-import path from 'path';
+import type { Linter } from 'eslint';
+import path from 'node:path';
 import { rules } from '../utils/rules';
 const base = require.resolve('./base');
 const baseExtend = path.extname(`${base}`) === '.ts' ? 'plugin:svelte/base' : base;
-export = {
+const config: Linter.Config = {
 	extends: [baseExtend],
 	rules: Object.fromEntries(
 		rules
@@ -16,3 +17,4 @@ export = {
 			)
 	)
 };
+export = config;

packages/eslint-plugin-svelte/src/configs/base.ts

@@ -1,7 +1,8 @@
 // IMPORTANT!
 // This file has been automatically generated,
 // in order to update its content execute "pnpm run update"
-export = {
+import type { Linter } from 'eslint';
+const config: Linter.Config = {
 	plugins: ['svelte'],
 	overrides: [
 		{
@@ -21,3 +22,4 @@ export = {
 		}
 	]
 };
+export = config;

packages/eslint-plugin-svelte/src/configs/flat/all.ts

@@ -1,6 +1,7 @@
+import type { Linter } from 'eslint';
 import { rules } from '../../utils/rules';
 import base from './base';
-export default [
+const config: Linter.FlatConfig[] = [
 	...base,
 	{
 		name: 'svelte:all:rules',
@@ -17,3 +18,4 @@ export default [
 		)
 	}
 ];
+export default config;

packages/eslint-plugin-svelte/src/configs/flat/base.ts

@@ -1,8 +1,8 @@
 // IMPORTANT!
 // This file has been automatically generated,
 // in order to update its content execute "pnpm run update"
-import type { ESLint } from 'eslint';
-export default [
+import type { ESLint, Linter } from 'eslint';
+const config: Linter.FlatConfig[] = [
 	{
 		name: 'svelte:base:setup-plugin',
 		plugins: {
@@ -33,3 +33,4 @@ export default [
 		processor: 'svelte/svelte'
 	}
 ];
+export default config;

packages/eslint-plugin-svelte/src/configs/flat/prettier.ts

@@ -1,8 +1,9 @@
 // IMPORTANT!
 // This file has been automatically generated,
 // in order to update its content execute "pnpm run update"
+import type { Linter } from 'eslint';
 import base from './base';
-export default [
+const config: Linter.FlatConfig[] = [
 	...base,
 	{
 		name: 'svelte:prettier:turn-off-rules',
@@ -22,3 +23,4 @@ export default [
 		}
 	}
 ];
+export default config;

packages/eslint-plugin-svelte/src/configs/flat/recommended.ts

@@ -1,8 +1,9 @@
 // IMPORTANT!
 // This file has been automatically generated,
 // in order to update its content execute "pnpm run update"
+import type { Linter } from 'eslint';
 import base from './base';
-export default [
+const config: Linter.FlatConfig[] = [
 	...base,
 	{
 		name: 'svelte:recommended:rules',
@@ -25,3 +26,4 @@ export default [
 		}
 	}
 ];
+export default config;

packages/eslint-plugin-svelte/src/configs/prettier.ts

@@ -1,10 +1,11 @@
 // IMPORTANT!
 // This file has been automatically generated,
 // in order to update its content execute "pnpm run update"
-import path from 'path';
+import type { Linter } from 'eslint';
+import path from 'node:path';
 const base = require.resolve('./base');
 const baseExtend = path.extname(`${base}`) === '.ts' ? 'plugin:svelte/base' : base;
-export = {
+const config: Linter.Config = {
 	extends: [baseExtend],
 	rules: {
 		// eslint-plugin-svelte rules
@@ -21,3 +22,4 @@ export = {
 		'svelte/shorthand-directive': 'off'
 	}
 };
+export = config;

packages/eslint-plugin-svelte/src/configs/recommended.ts

@@ -1,10 +1,11 @@
 // IMPORTANT!
 // This file has been automatically generated,
 // in order to update its content execute "pnpm run update"
-import path from 'path';
+import type { Linter } from 'eslint';
+import path from 'node:path';
 const base = require.resolve('./base');
 const baseExtend = path.extname(`${base}`) === '.ts' ? 'plugin:svelte/base' : base;
-export = {
+const config: Linter.Config = {
 	extends: [baseExtend],
 	rules: {
 		// eslint-plugin-svelte rules
@@ -24,3 +25,4 @@ export = {
 		'svelte/valid-compile': 'error'
 	}
 };
+export = config;

packages/eslint-plugin-svelte/tools/update-rulesets.ts

@@ -11,7 +11,8 @@ const legacyBaseContent = `/*
  * This file has been automatically generated,
  * in order to update its content execute "pnpm run update"
  */
-export = {
+import type { Linter } from 'eslint'
+const config: Linter.Config = {
   plugins: ["svelte"],
   overrides: [
     {
@@ -36,6 +37,7 @@ export = {
     },
   ],
 }
+export = config
 `;
 
 const legacyBaseFilePath = path.resolve(__dirname, '../src/configs/base.ts');
@@ -48,11 +50,12 @@ const legacyRecommendedContent = `/*
  * This file has been automatically generated,
  * in order to update its content execute "pnpm run update"
  */
-import path from "path"
+import type { Linter } from 'eslint'
+import path from "node:path"
 const base = require.resolve("./base")
 const baseExtend =
   path.extname(\`\${base}\`) === ".ts" ? "plugin:svelte/base" : base
-export = {
+const config: Linter.Config = {
   extends: [baseExtend],
   rules: {
     // eslint-plugin-svelte rules
@@ -65,6 +68,7 @@ export = {
 			.join(',\n    ')},
   },
 }
+export = config
 `;
 
 const legacyRecommendedFilePath = path.resolve(__dirname, '../src/configs/recommended.ts');
@@ -77,11 +81,12 @@ const legacyPrettierContent = `/*
  * This file has been automatically generated,
  * in order to update its content execute "pnpm run update"
  */
-import path from "path"
+import type { Linter } from 'eslint'
+import path from "node:path"
 const base = require.resolve("./base")
 const baseExtend =
   path.extname(\`\${base}\`) === ".ts" ? "plugin:svelte/base" : base
-export = {
+const config: Linter.Config = {
   extends: [baseExtend],
   rules: {
     // eslint-plugin-svelte rules
@@ -91,6 +96,7 @@ export = {
 			.join(',\n    ')},
   },
 }
+export = config
 `;
 
 const legacyPrettierFilePath = path.resolve(__dirname, '../src/configs/prettier.ts');
@@ -107,8 +113,8 @@ const baseContent = `/*
  * This file has been automatically generated,
  * in order to update its content execute "pnpm run update"
  */
-import type { ESLint } from 'eslint';
-export default [
+import type { ESLint, Linter } from 'eslint';
+const config: Linter.FlatConfig[] = [
   {
     name: 'svelte:base:setup-plugin',
     plugins: {
@@ -144,6 +150,7 @@ export default [
 		processor: 'svelte/svelte'
   },
 ]
+export default config
 `;
 
 const baseFilePath = path.resolve(__dirname, '../src/configs/flat/base.ts');
@@ -156,8 +163,9 @@ const recommendedContent = `/*
  * This file has been automatically generated,
  * in order to update its content execute "pnpm run update"
  */
+import type { Linter } from 'eslint';
 import base from "./base"
-export default [
+const config: Linter.FlatConfig[] = [
   ...base,
   {
     name: 'svelte:recommended:rules',
@@ -173,6 +181,7 @@ export default [
     },
   }
 ]
+export default config
 `;
 
 const recommendedFilePath = path.resolve(__dirname, '../src/configs/flat/recommended.ts');
@@ -185,8 +194,9 @@ const prettierContent = `/*
  * This file has been automatically generated,
  * in order to update its content execute "pnpm run update"
  */
+import type { Linter } from 'eslint';
 import base from "./base"
-export default [
+const config: Linter.FlatConfig[] = [
   ...base,
   {
     name: 'svelte:prettier:turn-off-rules',
@@ -199,6 +209,7 @@ export default [
     },
   }
 ]
+export default config
 `;
 
 const prettierFilePath = path.resolve(__dirname, '../src/configs/flat/prettier.ts');