| /** |
| * Copyright 2022 Google LLC. |
| * Copyright (c) Microsoft Corporation. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| import { type EventType, type Handler, type WildcardHandler } from 'mitt'; |
| export declare class EventEmitter<Events extends Record<EventType, unknown>> { |
| #private; |
| /** |
| * Binds an event listener to fire when an event occurs. |
| * @param event The event type you'd like to listen to. Can be a string or symbol. |
| * @param handler The function to be called when the event occurs. |
| * @return `this` to enable chaining method calls. |
| */ |
| on(type: '*', handler: WildcardHandler<Events>): this; |
| on<Key extends keyof Events>(type: Key, handler: Handler<Events[Key]>): this; |
| /** |
| * Like `on` but the listener will only be fired once and then it will be removed. |
| * @param event The event you'd like to listen to |
| * @param handler The handler function to run when the event occurs |
| * @return `this` to enable chaining method calls. |
| */ |
| once(event: EventType, handler: Handler): this; |
| /** |
| * Removes an event listener from firing. |
| * @param event The event type you'd like to stop listening to. |
| * @param handler The function that should be removed. |
| * @return `this` to enable chaining method calls. |
| */ |
| off(type: '*', handler: WildcardHandler<Events>): this; |
| off<Key extends keyof Events>(type: Key, handler: Handler<Events[Key]>): EventEmitter<Events>; |
| /** |
| * Emits an event and call any associated listeners. |
| * |
| * @param event The event to emit. |
| * @param eventData Any data to emit with the event. |
| * @return `true` if there are any listeners, `false` otherwise. |
| */ |
| emit<Key extends keyof Events>(event: Key, eventData: Events[Key]): void; |
| /** |
| * Removes all listeners. If given an event argument, it will remove only |
| * listeners for that event. |
| * @param event - the event to remove listeners for. |
| * @returns `this` to enable you to chain method calls. |
| */ |
| removeAllListeners(event?: EventType): this; |
| } |