@romanzy/web-event-emitter NPM

@romanzy/web-event-emitter

Browser based event emitter with full typescript support.

Installation

npm i @romanzy/web-event-emitter

Usage

Create an event map

export type MyEventMap = {
  ready: () => void;
  error: (message: string) => void;
};

Extend your class from WebEventEmitter. Now all events are typed.

export class MyClass extends WebEventEmitter<MyEventMap> {}

Additionally provides waitFor method. It works the same way as once, but returns a promise instead

API

  /**
   * Emits an event
   * @param event Event name
   * @param args Arguments to emit with
   */
  public emit<E extends keyof Events>(event: E, ...args: Arguments<Events[E]>): boolean

  /**
   * Subscribes to an event
   * @param event Event name
   * @param listener Callback function to execute when event is emitted
   * @returns
   */
  public on<E extends keyof Events>(event: E, listener: Events[E]): this

  /**
   * Subscribes to event once
   * @param event Event name
   * @param listener Callback function to execute when event is emitted
   * @returns
   */
  public once<E extends keyof Events>(event: E, listener: Events[E]): this

  /**
   * Waits for event to complete, currently never rejects
   * @param event Event name
   * @returns In async context returns event data as an array
   */
  public async waitFor<E extends keyof Events>(event: E): Promise<Arguments<Events[E]>>

  /**
   * Unsubscribes from event
   * @param event Event name
   * @param listener Callback function used when subscribed
   */
  public off<E extends keyof Events>(event: E, listener: Events[E]): this

  /**
   * Unsubscribes all from event. If no arguments are passed,
   * all events with given name are removed
   * @param event Event name
   * @returns
   */
  public offAll<E extends keyof Events>(event?: E): this