Angular2 - subscribe to Service variable changes

Question

I have an authentication service that makes the authenticated variable equal to true or false.

checkAuthentication(){
  this._authService.getAuthentication()
           


        

Answer 1

It depends on who needs to handle the event. If it's the parent component, you can leverage output event bindings:

@Output authenticationChange: EventEmitter = new EventEmitter();
checkAuthentication(){
     this._authService.getAuthentication()
     .subscribe(value => 
           if(value != this.authenticated) {
               this.authenticated = value);
               this.authenticationChange.emit(value);
      });
 }

And in your parent component: