no-empty-file: Fix directive check for TypeScript parser (#2180)

Co-authored-by: fisker Cheung <lionkay@gmail.com>

package.json

@@ -67,7 +67,7 @@
 		"@babel/core": "^7.22.8",
 		"@babel/eslint-parser": "^7.22.7",
 		"@lubien/fixture-beta-package": "^1.0.0-beta.1",
-		"@typescript-eslint/parser": "^5.61.0",
+		"@typescript-eslint/parser": "^6.2.0",
 		"ava": "^3.15.0",
 		"c8": "^8.0.0",
 		"chalk": "^5.3.0",

rules/no-empty-file.js

@@ -6,7 +6,7 @@ const messages = {
 	[MESSAGE_ID]: 'Empty files are not allowed.',
 };
 
-const isDirective = node => node.type === 'ExpressionStatement' && 'directive' in node;
+const isDirective = node => node.type === 'ExpressionStatement' && typeof node.directive === 'string';
 const isEmpty = node => isEmptyNode(node, isDirective);
 
 const isTripleSlashDirective = node =>

test/integration/projects.mjs

@@ -136,6 +136,8 @@ export default [
 			'aio/tools/transforms/authors-package/index.js', // This file use `package` keyword as variable
 			'packages/compiler-cli/test/**',
 			'tools/**',
+			// TODO[@fisker]: Check why it can't be parsed
+			'packages/forms/src/validators.ts',
 		],
 	},
 	// OOM

test/no-empty-file.mjs

@@ -77,3 +77,14 @@ test.snapshot({
 		].map(extension => ({code: '{}', filename: `example.${extension}`})),
 	],
 });
+
+// Test for https://github.com/sindresorhus/eslint-plugin-unicorn/issues/2175
+test.typescript({
+	valid: [
+		{code: '(() => {})();', filename: 'example.ts'},
+	],
+	invalid: [
+		{code: '"";', filename: 'example.ts', errors: 1},
+		{code: '"use strict";', filename: 'example.ts', errors: 1},
+	],
+});