keyv - adding in once event handler (#1171)

packages/keyv/package.json

@@ -1,6 +1,6 @@
 {
 	"name": "keyv",
-	"version": "5.1.1",
+	"version": "5.1.2",
 	"description": "Simple key-value storage with support for multiple backends",
 	"type": "module",
 	"main": "dist/index.cjs",

packages/keyv/src/event-manager.ts

@@ -51,6 +51,15 @@ class EventManager {
 		}
 	}
 
+	public once(event: string, listener: EventListener): void {
+		const onceListener: EventListener = (...arguments_: any[]) => {
+			listener(...arguments_);
+			this.off(event, onceListener);
+		};
+
+		this.on(event, onceListener);
+	}
+
 	// Emit an event
 	public emit(event: string, ...arguments_: any[]): void {
 		const listeners = this._eventListeners.get(event);

packages/keyv/test/event-manager.test.ts

@@ -124,3 +124,17 @@ test.it('if it is an error with no listeners throw error', () => {
 		emitter.emit('error', new Error('test'));
 	}).toThrow(Error);
 });
+
+test.it('once method', t => {
+	const emitter = new EventManager();
+	let dataReceived = 0;
+
+	emitter.once('test-event', () => {
+		dataReceived++;
+	});
+
+	emitter.emit('test-event');
+	emitter.emit('test-event');
+
+	t.expect(dataReceived).toBe(1);
+});