Method events

dom/src/MainDOMSource.ts:145–201

(eventType: string, options: EventsFnOptions = {})

  }

  public events(eventType: string, options: EventsFnOptions = {}): Stream<Event> {
    if (typeof eventType !== `string`) {
      throw new Error(`DOM driver's events() expects argument to be a ` +
        `string representing the event type to listen for.`);
    }
    const useCapture: boolean = determineUseCapture(eventType, options);

    const namespace = this._namespace;
    const fullScope = getFullScope(namespace);
    const keyParts = [eventType, useCapture];
    if (fullScope) {
      keyParts.push(fullScope);
    }
    const key = keyParts.join('~');
    const domSource = this;

    let rootElement$: Stream<Element>;
    if (fullScope) {
      rootElement$ = this._rootElement$
        .compose(filterBasedOnIsolation(domSource, fullScope));
    } else {
      rootElement$ = this._rootElement$.take(2);
    }

    const event$: Stream<Event> = rootElement$
      .map(function setupEventDelegatorOnTopElement(rootElement) {
        // Event listener just for the root element
        if (!namespace || namespace.length === 0) {
          return fromEvent(rootElement, eventType, useCapture);
        }

        // Event listener on the origin element as an EventDelegator
        const delegators = domSource._delegators;
        const origin = domSource._isolateModule.getElement(fullScope) || rootElement;
        let delegator: EventDelegator;
        if (delegators.has(key)) {
          delegator = delegators.get(key) as EventDelegator;
          delegator.updateOrigin(origin);
        } else {
          delegator = new EventDelegator(
            origin, eventType, useCapture, domSource._isolateModule,
          );
          delegators.set(key, delegator);
        }
        if (fullScope) {
          domSource._isolateModule.addEventDelegator(fullScope, delegator);
        }

        const subject = delegator.createDestination(namespace);
        return subject;
      })
      .flatten();

    const out: DevToolEnabledSource & Stream<Event> = adapt(event$);
    out._isCycleSource = domSource._name;
    return out;
  }