TypeScript gaming

_manager.ts

import * as EventEmitter from 'eventemitter3';

import {GameEvent} from "./game_event";
import {PlayerJoinedEvent} from "./player_joined_event";

export class Manager {
    private emitter: EventEmitter3.EventEmitter;
    
    constructor() {
        this.emitter = new EventEmitter();
    }
    
    public example(): void {
        // Register Listener
        let func = function(event: PlayerJoinedEvent ){
            console.info('Called PlayerJoinedEvent !');
            console.info('Player ' + event.getName() + ' has joined the game!');
        };
        this.addEventListener(SceneChangeEvent, func);
        
        // Emit the Event
        this.emit(new PlayerJoinedEvent('Sakura'));
    }
    
    /**
     * Register the GameEvent
     * @param event Class GameEvent what will listen to.
     * @param listener Callback function it receives GameEvent body as parameter.
     */
    public addEventListener(event: any, listener: (event: GameEvent) => void ): void {
        if (!event || !event.EVENT_NAME) {
            throw new Error('EVENT_NAME not defined in the specified event class');
        }
        this.emitter.addListener(event.EVENT_NAME, listener);
        console.log('Event registered: ' + event.EVENT_NAME);
    }

    /**
     * Emit the GameEvent
     * @param event GameEvent Body.
     */
    public emit(event: GameEvent ): void {
        this.emitter.emit(event.getEventName(), event);
        console.log('Event emitted: ' + event.getEventName());
    }
}

game_event.ts

export abstract class GameEvent {
    public static get EVENT_NAME(): string { return null; }

    constructor() { }

    public getEventName(): string {
        let event: any = <typeof GameEvent>this.constructor;
        if (!event.EVENT_NAME) {
            throw new Error('EVENT_NAME not defined in the specified event class');
        }
        return event.EVENT_NAME;
    }
}

player_joined_event.ts

import {GameEvent} from './game_event';

export class PlayerJoinedEvent extends GameEvent {
    public static get EVENT_NAME(): string { return 'player_joined'; }

    private name: string;
    
    public getName(): string {
        return this.name;
    }

    constructor(name: string ) {
        super();
        this.name = name;
    }
}