chore: add playground

Author: StyleShit

.gitignore

@@ -12,6 +12,8 @@ coverage
 dist
 dist-ssr
 *.local
+playground/*
+!playground/.gitkeep
 
 # Editor directories and files
 .vscode/*

README.md

@@ -50,3 +50,7 @@ export default defineConfig([
 | `php/eqeqeq`              | Require the use of `===` and `!==`                  |     |     |
 | `php/no-array-keyword`    | Disallow the use of the array keyword               | 🔧  |     |
 | `php/require-visibility`  | Require visibility for class methods and properties |     | 💡  |
+
+## Development
+
+Use `npm run playground` to lint local PHP files under the `playground` directory.

eslint.config.playground.mjs

@@ -0,0 +1,38 @@
+/* eslint-disable no-console */
+import fs from 'fs';
+import { defineConfig } from 'eslint/config';
+
+if (!fs.existsSync('./dist/index.js')) {
+	console.error('Please run `npm run build` before using the playground.');
+
+	process.exit(1);
+}
+
+const phpFiles = fs
+	.readdirSync('./playground')
+	.filter((file) => file.endsWith('.php'));
+
+if (phpFiles.length === 0) {
+	console.error(
+		'Please add PHP files to `/playground` before using the playground.',
+	);
+
+	process.exit(1);
+}
+
+const php = (await import('./dist/index.js')).default;
+
+export default defineConfig({
+	files: ['./**/*.php'],
+	plugins: {
+		php,
+	},
+	language: 'php/php',
+	rules: {
+		// TODO: Use recommended config.
+		'php/eqeqeq': 'error',
+		'php/disallow-references': 'error',
+		'php/no-array-keyword': 'error',
+		'php/require-visibility': 'error',
+	},
+});

package.json

@@ -40,7 +40,8 @@
 		"format": "prettier --write ./",
 		"format:check": "prettier --check ./",
 		"build": "tsup",
-		"release": "npm run build && changeset publish"
+		"release": "npm run build && changeset publish",
+		"playground": "eslint ./playground --config=eslint.config.playground.mjs"
 	},
 	"devDependencies": {
 		"@changesets/cli": "^2.27.7",