events-hub.service.ts
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import { Injectable, Inject, OpaqueToken, EventEmitter } from 'ng-forward';
export const EVENTS_HUB_KNOW_EVENT_NAMES = new OpaqueToken('EVENTS_HUB_KNOW_EVENT_NAMES');
export interface EventsHubKnownEventNames {
getNames(): string[];
}
function isEventsHubKnownEventNames(object: any): object is EventsHubKnownEventNames {
return 'getNames' in object;
}
@Injectable()
@Inject(EVENTS_HUB_KNOW_EVENT_NAMES)
export class EventsHubService {
private emitters: Map<string, EventEmitter<any>>;
private knownEvents: string[] = [];
constructor(private eventsHubKnownEventNames: EventsHubKnownEventNames | string[]) {
if (isEventsHubKnownEventNames(eventsHubKnownEventNames)) {
this.knownEvents = eventsHubKnownEventNames.getNames();
} else if (Array.isArray(eventsHubKnownEventNames)) {
this.knownEvents = eventsHubKnownEventNames;
}
this.emitters = new Map<string, EventEmitter<any>>();
this.setupEmitters();
}
emitEvent(eventType: string, payload?: any) {
this.checkKnownEvent(eventType);
let event = this.emitters.get(eventType);
if (event) this.emitters.get(eventType).next(payload);
}
subscribeToEvent<T>(eventType: string, generatorOrNext?: ((p?: T) => void), error?: any, complete?: any) {
this.checkKnownEvent(eventType);
let event = this.emitters.get(eventType);
if (event) event.subscribe(generatorOrNext, error, complete);
}
private setupEmitters() {
for (let i: number = 0; i < this.knownEvents.length; i++) {
this.emitters.set(this.knownEvents[i], new EventEmitter<any>());
}
}
private checkKnownEvent(eventType: string) {
if (!this.emitters.has(eventType)) {
throw new Error('Unknown event named ' + eventType.toString());
}
}
}