deps: update eslint to v9

html-to-react/eslint.config.mjs

@@ -0,0 +1,52 @@
+import { defineConfig } from 'eslint/config'
+import typescriptEslint from '@typescript-eslint/eslint-plugin'
+import prettier from 'eslint-plugin-prettier'
+import tsParser from '@typescript-eslint/parser'
+import path from 'node:path'
+import { fileURLToPath } from 'node:url'
+import js from '@eslint/js'
+import { FlatCompat } from '@eslint/eslintrc'
+import prettierConfig from './.prettierrc.json' with { type: 'json' }
+import vitest from '@vitest/eslint-plugin'
+
+const __filename = fileURLToPath(import.meta.url)
+const __dirname = path.dirname(__filename)
+const compat = new FlatCompat({
+  baseDirectory: __dirname,
+  recommendedConfig: js.configs.recommended,
+  allConfig: js.configs.all
+})
+
+export default defineConfig([
+  {
+    extends: compat.extends(
+      'eslint:recommended',
+      'plugin:@typescript-eslint/eslint-recommended',
+      'plugin:@typescript-eslint/recommended-requiring-type-checking',
+      'plugin:@typescript-eslint/recommended',
+      'prettier'
+    ),
+
+    plugins: {
+      '@typescript-eslint': typescriptEslint,
+      prettier,
+      vitest
+    },
+
+    languageOptions: {
+      parser: tsParser,
+      ecmaVersion: 5,
+      sourceType: 'script',
+
+      parserOptions: {
+        project: ['./tsconfig.test.json']
+      }
+    },
+
+    rules: {
+      'prettier/prettier': ['error', prettierConfig],
+
+      ...vitest.configs.recommended.rules
+    }
+  }
+])