fix: handle thrown errors within async handlers (#135)

* fix uncaught async error

* Add test

* chore: truncate

* fix bad merge conflict

* chore: add extra async-throw test

Co-authored-by: Luke Edwards <[email protected]>

packages/polka/index.js

@@ -70,14 +70,9 @@ class Polka extends Router {
 		req.query = info.query || {};
 		req.search = info.search;
 
-		try {
-			let i=0, arr=obj.handlers.concat(this.onNoMatch), len=arr.length;
-			let loop = () => res.finished || (i < len) && arr[i++](req, res, next);
-			next = next || (err => err ? this.onError(err, req, res, next) : loop());
-			loop(); // init
-		} catch (err) {
-			this.onError(err, req, res, next);
-		}
+		let i=0, arr=obj.handlers.concat(this.onNoMatch), len=arr.length;
+		let loop = async () => res.finished || (i < len) && arr[i++](req, res, next);
+		(next = next || (err => err ? this.onError(err, req, res, next) : loop().catch(next)))(); // init
 	}
 }
 

packages/polka/test/index.js

@@ -959,6 +959,52 @@ test('errors – `throw Error`', async () => {
 });
 
 
+test('errors – `throw Error` :: async', async () => {
+	let app = (
+		polka()
+			.use(async () => {
+				let err = new Error('hello');
+				err.code = 418;
+				throw err;
+			})
+			.get('/', (req, res) => {
+				val = 123; // wont run
+				res.end('OK');
+			})
+	);
+
+	let val = 42;
+	let uri = $.listen(app);
+	await get(uri).catch(err => {
+		assert.is(val, 42, 'exits without running route handler');
+    assert.is(err.statusCode, 418, '~> received custom status');
+		assert.is(err.data, 'hello', '~> received "hello" text');
+	});
+
+	app.server.close();
+});
+
+test('errors – `throw Error` :: async :: subapp', async () => {
+	let sub = polka().use(async () => {
+		throw new Error('busted');
+	});
+
+	let app = polka().use('/sub', sub, (req, res) => {
+		val = 123; // wont run
+		res.end('OK');
+	});
+
+	let val = 42;
+	let uri = $.listen(app);
+	await get(uri + '/sub/123').catch(err => {
+		assert.is(val, 42, 'exits without running route handler');
+    assert.is(err.statusCode, 500, '~> received default status');
+		assert.is(err.data, 'busted', '~> received "busted" text');
+	});
+
+	app.server.close();
+});
+
 test('errors – `throw msg`', async () => {
 	// t.plan(3);