Upgrade to ESLint 9 (#5)

Author: knutkirkhorn

.eslintrc.json

@@ -0,0 +1,34 @@
+import js from '@eslint/js';
+import eslintConfigPrettier from 'eslint-config-prettier';
+import eslintPluginUnicorn from 'eslint-plugin-unicorn';
+import {defineConfig} from 'eslint/config';
+import globals from 'globals';
+
+export default defineConfig([
+	js.configs.recommended,
+	eslintPluginUnicorn.configs.recommended,
+	eslintConfigPrettier,
+	{
+		languageOptions: {
+			globals: {...globals.node},
+
+			ecmaVersion: 2025,
+			sourceType: 'module',
+		},
+
+		rules: {
+			// Disable rules
+			'no-console': 'off',
+			'no-plusplus': 'off',
+			'no-await-in-loop': 'off',
+			'no-restricted-syntax': 'off',
+
+			// Enable rules
+			'no-param-reassign': 'error',
+			'consistent-return': 'error',
+			'no-else-return': 'error',
+			'no-var': 'error',
+			'prefer-const': 'error',
+		},
+	},
+]);