Classic EventEmitter for TypeScript

import { EventEmitter } from 'eventemitter-ts';


type Shifts = 'R' | 'N' | 1 | 2 | 3 | 5 | 6

/// Define event map
export interface ErrorEvent extends Error {}

interface CarBaseEvent<T> {
  readonly car: Car;
  readonly data: T;
}

export interface FuelLevel extends CarBaseEvent<number> {}

export interface TransmissionChange extends CarBaseEvent<Shifts> {}

export interface CarEventMap {
  error: ErrorEvent;
  fuel: FuelLevel;
  shift: TransmissionChange;
}

/// Extend target class

class Car extends EventEmitter<CarEventMap> {
  private fuel: number = 0

  public goto(loc: string){
    if (this.fuel <= 0) {
      this.emit('error', new Error('Not enough fuel!'))
    }
  }

  public refuel(data: number) {
    this.fuel = data
    this.emit('fuel', {car: this, data})
  }

  public shift(data: Shifts) {
    this.emit('shift', {car: this, data: 1})
  }

  public destroy(){
    this.off()
  }

}

/// Add listener

const car = new Car()

car.on('shift', (event) => {
  console.log(`👋 shift -> ${event.data}`)
})

car.shift('R')