src/js/event.js

export class EventEmitter {
    constructor() {
        this.listeners = new Map();
    }

    on(event, callback) {
        if (!this.listeners.has(event)) {
            this.listeners.set(event, new Set());
        }
        this.listeners.get(event).add(callback);
    }

    off(event, callback) {
        if (this.listeners.has(event)) {
            this.listeners.get(event).delete(callback);
        }
    }

    emit(event, ...args) {
        if (this.listeners.has(event)) {
            this.listeners.get(event).forEach(callback => callback(...args));
        }
    }

    clear() {
        this.listeners.clear();
    }
}

export const EventTypes = {
    KEY_DOWN: 'keydown',
    KEY_UP: 'keyup',
    KEY_PRESS: 'keypress',
    MOUSE_MOVE: 'mousemove',
    MOUSE_DOWN: 'mousedown',
    MOUSE_UP: 'mouseup',
    MOUSE_WHEEL: 'wheel',
    CLICK: 'click'
};