Add support for events triggered on text nodes (#21)

index.ts

@@ -63,6 +63,21 @@ function isEventTarget(
 	return typeof (elements as EventTarget).addEventListener === 'function';
 }
 
+function safeClosest(event: Event, selector: string): Element | void {
+	let target = event.target;
+	if (target instanceof Text) {
+		target = target.parentElement;
+	}
+
+	if (target instanceof Element && event.currentTarget instanceof Element) {
+		// `.closest()` may match ancestors of `currentTarget` but we only need its children
+		const closest = target.closest(selector);
+		if (closest && event.currentTarget.contains(closest)) {
+			return closest;
+		}
+	}
+}
+
 /**
  * Delegates event to a selector.
  */
@@ -99,18 +114,10 @@ function delegate<
 
 	// Handle the regular Element usage
 	const capture = Boolean(typeof options === 'object' ? options.capture : options);
-	const listenerFn: EventListener = (event: Partial<delegate.Event>): void => {
-		const delegateTarget = (event.target as Element).closest(selector) as TElement;
-
-		if (!delegateTarget) {
-			return;
-		}
-
-		event.delegateTarget = delegateTarget;
-
-		// Closest may match elements outside of the currentTarget
-		// so it needs to be limited to elements inside it
-		if ((event.currentTarget as Element).contains(event.delegateTarget)) {
+	const listenerFn: EventListener = (event: Event): void => {
+		const delegateTarget = safeClosest(event, selector);
+		if (delegateTarget) {
+			(event as any).delegateTarget = delegateTarget;
 			callback.call(baseElement, event as delegate.Event<TEvent, TElement>);
 		}
 	};

test.js

@@ -16,9 +16,11 @@ const {window} = new JSDOM(`
     </ul>
 `);
 
+global.Text = window.Text;
 global.Event = window.Event;
 global.Element = window.Element;
 global.Document = window.Document;
+global.MouseEvent = window.MouseEvent;
 global.document = window.document;
 const container = window.document.querySelector('ul');
 const anchor = window.document.querySelector('a');
@@ -46,6 +48,11 @@ test.serial('should add an event listener only once', t => {
 	anchor.click();
 });
 
+test.serial('should handle events on text nodes', t => {
+	delegate(container, 'a', 'click', t.pass);
+	anchor.firstChild.dispatchEvent(new MouseEvent('click', {bubbles: true}));
+});
+
 test.serial('should remove an event listener', t => {
 	const spy = sinon.spy(container, 'removeEventListener');