Better EventEmitter TypeScript interface

EventListener.d.ts

export class EventEmitter<Events, K = keyof Events|symbol> {
  addListener(event: K, listener: (...args: any[]) => void): this;
  on(event: K, listener: (...args: any[]) => void): this;
  once(event: K, listener: (...args: any[]) => void): this;
  removeListener(event: K, listener: (...args: any[]) => void): this;
  removeAllListeners(event?: K): this;
  setMaxListeners(n: number): this;
  getMaxListeners(): number;
  listeners(event: K): Function[];
  emit(event: K, ...args: any[]): boolean;
  listenerCount(type: K): number;
  // Added in Node 6...
  prependListener(event: K, listener: (...args: any[]) => void): this;
  prependOnceListener(event: K, listener: (...args: any[]) => void): this;
  eventNames(): (K)[];
}

x-example.ts

interface PingEvent extends Event {
  msg :string
}

interface FooEvents {
  "change": Event,
  "ping": PingEvent
}

class Foo extends EventEmitter<FooEvents> {
  triggerPing(msg :string) {
    this.emit("ping", msg)
  }
}

const foo = new Foo()
foo.on("ping", msg => console.log('ping event with message', msg))
foo.triggerPing('hello')