Fix spawn handling

sindresorhus · sindresorhus · commit 966239c1edc7 · 2025-11-12T12:50:47.000+07:00
Fixes #144 Fixes #189
diff --git a/index.js b/index.js
@@ -268,7 +268,19 @@ const baseOpen = async options => {
 
 	subprocess.unref();
 
-	return subprocess;
+	// Handle spawn errors before the caller can attach listeners.
+	// This prevents unhandled error events from crashing the process.
+	return new Promise((resolve, reject) => {
+		subprocess.once('error', reject);
+
+		// Wait for the subprocess to spawn before resolving.
+		// This ensures the process is established before the caller continues,
+		// preventing issues when process.exit() is called immediately after.
+		subprocess.once('spawn', () => {
+			subprocess.off('error', reject);
+			resolve(subprocess);
+		});
+	});
 };
 
 const open = (target, options) => {
diff --git a/test.js b/test.js
@@ -1,3 +1,4 @@
+import process from 'node:process';
 import test from 'ava';
 import open, {openApp, apps} from './index.js';
 
@@ -105,3 +106,18 @@ test('open default browser', async t => {
 test('open default browser in incognito mode', async t => {
 	await t.notThrowsAsync(openApp(apps.browserPrivate, {newInstance: true}));
 });
+
+test('subprocess is spawned before promise resolves', async t => {
+	const childProcess = await open('index.js');
+
+	// By the time the promise resolves, the spawn event should have fired
+	// We verify this by checking that the subprocess has a pid
+	t.true(childProcess.pid !== undefined && childProcess.pid !== null);
+});
+
+if (process.platform === 'linux') {
+	test('spawn errors reject the promise instead of crashing', async t => {
+		const error = await t.throwsAsync(openApp('definitely-not-a-real-command-12345'));
+		t.is(error.code, 'ENOENT');
+	});
+}
