Loading State Service with dispenser in Angular2

loading-state.service.ts

import { Injectable } from '@angular/core';
import { Subject } from 'rxjs/Subject';

interface State {
  isLoading: boolean;
  blockerLoading: boolean;
}

/**
 * Responsible by loadingState
 */
@Injectable()
export class LoadingStateService {
  public state: State = {
    isLoading: true,
    blockerLoading: true
  };

  public stateChange: Subject<State> = new Subject<State>();

  private dispensers: Array<Number> = [];

  private setState(isLoading: boolean, blockerLoading: boolean) {
    this.state = {
      isLoading,
      blockerLoading
    }

    this.stateChange.next(this.state);
  }

  validateDispensers(dispenseUid: Number): Boolean {
    this.cleanDispenser(dispenseUid);

    return this.dispensers.length > 0;
  }

  stopLoading(dispenseUid: Number = null) {
    if(this.validateDispensers(dispenseUid)) return;

    this.setState(false, false);
  }

  startLoading(blocker = false, dispenseUid: Number = null) {
    if(this.validateDispensers(dispenseUid)) return;

    this.setState(false, blocker);
  }

  startBlockLoading(dispenseUid: Number = null) {
    if(this.validateDispensers(dispenseUid)) return;

    this.startLoading(true);
  }

  registerDispenser(blocker = false) {
    var dispenserUid = Date.now();
    this.dispensers.push(dispenserUid);

    var Dispenser = {
        dispenserUid,
	dispense: function() {
          this.stopLoading(Dispenser.dispenserUid);
	}
    };

    // bind context in Dispenser!
    Dispenser.dispense = Dispenser.dispense.bind(this);
    this.startLoading(blocker);

    return Dispenser;
  }

  cleanDispenser(dispenseUid: Number) {
    this.dispensers = this.dispensers.filter((dispenser) => {
      return dispenser !== dispenseUid
    });
  }
}