feat: support fs.exists async function

src/fs.ts

@@ -0,0 +1,17 @@
+import { Stats } from 'node:fs';
+import { stat } from 'node:fs/promises';
+
+/**
+ * Check if a file exists.
+ * Returns the file stats if it exists, or `false` if it doesn't.
+ */
+export async function exists(file: string): Promise<Stats | false> {
+  try {
+    return await stat(file);
+  } catch (err: any) {
+    if (err.code === 'ENOENT') {
+      return false;
+    }
+    throw err;
+  }
+}

src/index.ts

@@ -9,3 +9,4 @@ export * from './string.js';
 export * from './optimize.js';
 export * from './object.js';
 export * from './timeout.js';
+export * from './fs.js';

test/fs.test.ts

@@ -0,0 +1,30 @@
+import { strict as assert } from 'node:assert';
+import path from 'node:path';
+import { Stats } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+import * as utility from '../src/index.js';
+import { exists } from '../src/index.js';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+describe('test/fs.test.ts', () => {
+  describe('exists()', () => {
+    it('should work', async () => {
+      let stats = await exists(__filename);
+      assert(stats instanceof Stats);
+      assert(stats.size > 0, 'stats.size > 0');
+      assert.equal(stats.isFile(), true);
+      assert.equal(stats.isDirectory(), false);
+
+      stats = await utility.exists(__dirname);
+      assert(stats instanceof Stats);
+      assert(stats.size > 0, 'stats.size > 0');
+      assert.equal(stats.isDirectory(), true);
+      assert.equal(stats.isFile(), false);
+      assert.equal(await exists(__dirname + '/nonexistent'), false);
+
+      assert.equal(await exists('/root/../../../../../etc/passwd'), false);
+    });
+  });
+});