@synet/patterns/dist/patterns/event-emitter.js

Robust, battle-tested collection of stable patterns used in Synet packages

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.EventEmitter = void 0;
/**
 * EventEmitter that maintains a list of observers and notifies them of events
 */
class EventEmitter {
    constructor() {
        this.observers = new Map();
    }
    /**
     * Subscribe to events of a specific type
     */
    subscribe(eventType, observer) {
        const observers = this.observers.get(eventType) || [];
        if (!observers.includes(observer)) {
            observers.push(observer);
            this.observers.set(eventType, observers);
        }
    }
    /**
     * Unsubscribe from events of a specific type
     */
    unsubscribe(eventType, observer) {
        const observers = this.observers.get(eventType);
        if (!observers)
            return;
        const index = observers.indexOf(observer);
        if (index !== -1) {
            observers.splice(index, 1);
            if (observers.length === 0) {
                this.observers.delete(eventType);
            }
            else {
                this.observers.set(eventType, observers);
            }
        }
    }
    /**
     * Emit an event to all subscribed observers
     */
    emit(event) {
        const observers = this.observers.get(event.type) || [];
        for (const observer of observers) {
            observer.update(event);
        }
    }
    /**
     * Check if there are any subscribers for a specific event type
     */
    hasObservers(eventType) {
        return (this.observers.has(eventType) &&
            (this.observers.get(eventType)?.length ?? 0) > 0);
    }
}
exports.EventEmitter = EventEmitter;