Use better connection error object in browser

Author: t2t2

src/base.ts

@@ -78,11 +78,18 @@ export abstract class BaseOBSWebSocket extends EventEmitter<MapValueToArgsArray<
 					this.emit('Hello', hello);
 					return this.identify(hello, password, identificationParams);
 				})(),
-				connectionClosedPromise.then(e => {
-					throw e;
-				}),
-				connectionErrorPromise.then(e => {
-					throw e;
+				// Choose the best promise for connection error/close
+				// In browser connection close has close code + reason,
+				// while in node error event has these
+				new Promise<never>((resolve, reject) => {
+					void connectionErrorPromise.then(e => {
+						if (e.message) {
+							reject(e);
+						}
+					});
+					void connectionClosedPromise.then(e => {
+						reject(e);
+					});
 				}),
 			]);
 		} catch (error: unknown) {

tests/invalid-server.test.ts

@@ -85,3 +85,32 @@ test('server returns wrong protocol', async t => {
 
 	await obs.disconnect();
 });
+
+test('no server listening', async t => {
+	const obs = new OBSWebSocket();
+
+	// Temporarily create a websocket server to guarantee an unused port
+	const port = await new Promise<number>(resolve => {
+		const server = new WebSocketServer({
+			port: 0,
+			handleProtocols() {
+				return 'dummy';
+			},
+		}, () => {
+			const {port} = server.address() as AddressInfo;
+			server.close(() => {
+				resolve(port);
+			});
+		});
+	});
+
+	t.false(obs.identified);
+	await t.throwsAsync(obs.connect(`ws://127.0.0.1:${port}`), {
+		instanceOf: OBSWebSocketError,
+		message: `connect ECONNREFUSED 127.0.0.1:${port}`,
+		code: -1,
+	});
+	t.false(obs.identified);
+
+	await obs.disconnect();
+});