UIHandler: ignore rejections from the underlying makeRequest() call i…

…n UI interactions

src/core/UIHandler.ts

@@ -68,11 +68,16 @@ export class UIHandler extends EventTarget {
 		const element = event.currentTarget;
 		const options: Options = {};
 
+		const ignoreErrors = () => {
+			// don't reject the promise in case of an error as developers have no way of handling the rejection
+			// in this situation; errors should be handled in `naja.addEventListener('error', errorHandler)`
+		};
+
 		if (event.type === 'submit') {
-			this.submitForm(element as HTMLFormElement, options, event);
+			this.submitForm(element as HTMLFormElement, options, event).catch(ignoreErrors);
 
 		} else if (event.type === 'click') {
-			this.clickElement(element as HTMLElement, options, mouseEvent);
+			this.clickElement(element as HTMLElement, options, mouseEvent).catch(ignoreErrors);
 		}
 	}
 

tests/Naja.UIHandler.js

@@ -330,6 +330,26 @@ describe('UIHandler', function () {
 			mock.verify();
 		});
 
+		it('failed request should not cause unhandled rejection', function () {
+			const naja = mockNaja();
+			const mock = sinon.mock(naja);
+			mock.expects('makeRequest')
+				.withExactArgs('GET', 'http://localhost:9876/UIHandler/a', null, {})
+				.once()
+				.returns(Promise.reject(new Error()));
+
+			const handler = new UIHandler(naja);
+
+			const evt = {
+				type: 'click',
+				currentTarget: this.a,
+				preventDefault: () => undefined,
+			};
+			handler.handleUI(evt);
+
+			mock.verify();
+		});
+
 		it('a.ajax', function () {
 			const naja = mockNaja();
 			const mock = sinon.mock(naja);