chore(deps): update dependency eslint to v9 (#174)

* chore(deps): update dependency eslint to v9

* chore: eslint 9

---------

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: AriPerkkio <ari.perkkio@gmail.com>

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
         strategy:
             fail-fast: false
             matrix:
-                node-version: [16, 18]
+                node-version: [18, 20]
 
         steps:
             - uses: actions/checkout@v4
@@ -44,7 +44,7 @@ jobs:
         strategy:
             fail-fast: false
             matrix:
-                node-version: [16, 18]
+                node-version: [18, 20]
                 example-name: [example-basic, example-workspace]
 
         steps:

.github/workflows/vitest-latest-compatibility.yml

@@ -43,7 +43,7 @@ jobs:
         strategy:
             fail-fast: false
             matrix:
-                node-version: [16, 18]
+                node-version: [18, 20]
                 example-name: [example-basic, example-workspace]
 
         steps:

eslint.config.js

@@ -0,0 +1,51 @@
+import { readFileSync } from 'node:fs';
+import js from '@eslint/js';
+import tseslint from 'typescript-eslint';
+import eslintPluginUnicorn from 'eslint-plugin-unicorn';
+import { FlatCompat } from '@eslint/eslintrc';
+import eslintPluginPrettierRecommended from 'eslint-plugin-prettier/recommended';
+
+const tsconfig = JSON.parse(readFileSync('./tsconfig.json', 'utf8'));
+const compat = new FlatCompat({ baseDirectory: import.meta.dirname });
+
+export default defineConfig([
+    js.configs.recommended,
+    ...tseslint.configs.recommended,
+    ...tseslint.configs.recommendedTypeChecked.map((config) => ({
+        ...config,
+        files: tsconfig.include,
+    })),
+    {
+        files: tsconfig.include,
+        languageOptions: {
+            parserOptions: {
+                project: true,
+                tsconfigRootDir: import.meta.dirname,
+            },
+        },
+    },
+    {
+        plugins: { unicorn: eslintPluginUnicorn },
+        rules: { 'unicorn/prefer-node-protocol': 'error' },
+    },
+    ...compat.plugins('eslint-plugin-import'),
+    {
+        // Require specifying extensions due to https://github.com/microsoft/TypeScript/issues/16577
+        files: ['src/**'],
+        rules: { 'import/extensions': ['error', 'always'] },
+    },
+    {
+        files: ['test/**'],
+        rules: {
+            '@typescript-eslint/no-unsafe-argument': 'off',
+            '@typescript-eslint/no-unsafe-assignment': 'off',
+        },
+    },
+    { ignores: ['dist', '.eslintrc.cjs'] },
+    eslintPluginPrettierRecommended,
+]);
+
+/** @param config {import('eslint').Linter.FlatConfig} */
+function defineConfig(config) {
+    return config;
+}

package.json

@@ -22,22 +22,24 @@
         "prebuild": "rm -rf ./dist",
         "build": "tsc --project tsconfig.prod.json",
         "start": "vitest --update",
-        "lint": "eslint . --max-warnings 0 --ext .ts && publint",
+        "lint": "eslint . --max-warnings 0 && publint",
         "test": "vitest",
         "validate": "pnpm build && pnpm lint && pnpm test run"
     },
     "devDependencies": {
+        "@eslint/eslintrc": "^3.0.2",
+        "@eslint/js": "^9.0.0",
+        "@types/eslint": "^8.56.9",
         "@types/node": "^20.12.7",
-        "@typescript-eslint/eslint-plugin": "^7.6.0",
-        "@typescript-eslint/parser": "^7.6.0",
-        "eslint": "^8.57.0",
+        "eslint": "^9.0.0",
         "eslint-config-prettier": "^9.1.0",
         "eslint-plugin-import": "^2.29.1",
         "eslint-plugin-prettier": "^5.1.3",
         "eslint-plugin-unicorn": "^52.0.0",
         "prettier": "^3.2.5",
         "publint": "^0.2.7",
         "typescript": "^5.4.5",
+        "typescript-eslint": "^7.6.0",
         "vite": "^5.2.8",
         "vitest": "^1.5.0"
     },