Fix support for typed subscriptions for multiple event names for .on()

index.d.ts

@@ -12,7 +12,10 @@ type DatalessEventNames<EventData> = {
 
 declare const listenerAdded: unique symbol;
 declare const listenerRemoved: unique symbol;
-type OmnipresentEventData = {[listenerAdded]: Emittery.ListenerChangedData; [listenerRemoved]: Emittery.ListenerChangedData};
+type OmnipresentEventData = {
+	[listenerAdded]: Emittery.ListenerChangedData;
+	[listenerRemoved]: Emittery.ListenerChangedData;
+};
 
 /**
 Emittery is a strictly typed, fully async EventEmitter implementation. Event listeners can be registered with `on` or `once`, and events can be emitted with `emit`.
@@ -149,7 +152,7 @@ declare class Emittery<
 	```
 	*/
 	on<Name extends keyof AllEventData>(
-		eventName: Name,
+		eventName: Name | Name[],
 		listener: (eventData: AllEventData[Name]) => void | Promise<void>
 	): Emittery.UnsubscribeFn;
 
@@ -292,7 +295,9 @@ declare class Emittery<
 	emitter.emit('🐶', '🍖'); // Nothing happens
 	```
 	*/
-	once<Name extends keyof AllEventData>(eventName: Name): Promise<AllEventData[Name]>;
+	once<Name extends keyof AllEventData>(
+		eventName: Name
+	): Promise<AllEventData[Name]>;
 
 	/**
 	Trigger an event asynchronously, optionally with some data. Listeners are called in the order they were added, but executed concurrently.
@@ -404,7 +409,10 @@ declare class Emittery<
 	object.emit('event');
 	```
 	*/
-	bindMethods(target: Record<string, unknown>, methodNames?: readonly string[]): void;
+	bindMethods(
+		target: Record<string, unknown>,
+		methodNames?: readonly string[]
+	): void;
 }
 
 declare namespace Emittery {

index.test-d.ts

@@ -19,6 +19,7 @@ type AnyListener = (eventData?: unknown) => void | Promise<void>;
 	ee.on('anEvent', async () => Promise.resolve());
 	ee.on('anEvent', data => undefined);
 	ee.on('anEvent', async data => Promise.resolve());
+	ee.on(['anEvent', 'anotherEvent'], async data => undefined);
 	ee.on(Emittery.listenerAdded, ({eventName, listener}) => {
 		expectType<string | symbol | undefined>(eventName);
 		expectType<AnyListener>(listener);