feat: Event.clear() to remove all listeners

src/sync.ts

@@ -197,6 +197,18 @@ export class Event<Parent, Args extends any[] = []> {
 		}
 	}
 
+	/**
+	 * Clear all listeners for this event.
+	 */
+	public clear() {
+		this.registeredListeners = undefined;
+
+		if(this.monitor) {
+			// Trigger the monitor if available
+			this.monitor(this);
+		}
+	}
+
 	/**
 	 * Monitor for changes to listeners. Only a single monitor is supported at
 	 * a single time. This is intended to be used to react to if listeners are

test/sync.test.ts

@@ -351,6 +351,21 @@ describe('Synchronous event', function() {
 		expect(triggered).toEqual(2);
 	});
 
+	it('clear removes all listeners', function() {
+		const parent = {};
+		const handler = new Event(parent);
+
+		let triggered = 0;
+		handler.subscribable(() => {
+			triggered++;
+		});
+
+		handler.clear();
+		handler.emit();
+
+		expect(triggered).toEqual(0);
+	});
+
 	it('Monitor is notified about single listener', function() {
 		const parent = {};
 		const handler = new Event(parent);
@@ -411,6 +426,22 @@ describe('Synchronous event', function() {
 		expect(triggerCount).toEqual(1);
 	});
 
+	it('Monitor is notified about clear', function() {
+		const parent = {};
+		const handler = new Event(parent);
+
+		handler.subscribe(() => {});
+
+		let triggerCount = 0;
+		handler.monitorListeners(() => {
+			triggerCount++;
+		});
+
+		handler.clear();
+
+		expect(triggerCount).toEqual(1);
+	});
+
 	it('listeners returns single listener', function() {
 		const parent = {};
 		const handler = new Event(parent);