angular - BehaviorSubject undefined in constructor -

i have problem behaviorsubjects.

i have service :

import{ injectable } '@angular/core'; import { behaviorsubject } 'rxjs/behaviorsubject';  @injectable() export class boutonimprimergriseservice {      boutonimprimergrise = new behaviorsubject<boolean>(true);     boutonimprimergrisechanged$ = this.boutonimprimergrise.asobservable();      boutonmettreazerogrise = new behaviorsubject<boolean>(true);     boutonmettreazerogrisechanged$ = this.boutonmettreazerogrise.asobservable();  } 

and use in component :

export class gestioncompteurscomponent {  boutonimprimergrise: boolean; boutonmettreazerogrise: boolean;  private _boutonimprimergrisesubscription: subscription; private _boutonmettreazerosubscription: subscription;  constructor(private _boutonimprimergriseservice: boutonimprimergriseservice) {     this._boutonimprimergrisesubscription = this._boutonimprimergriseservice.boutonimprimergrisechanged$.subscribe(         value => {             console.log(value);             this.boutonimprimergrise = value;         }     );     this._boutonmettreazerosubscription = this._boutonimprimergriseservice.boutonmettreazerogrisechanged$.subscribe(         value => {             console.log(value);             this.boutonmettreazerogrise = value;         }     ); } } 

the problem when log values of observables in constructor, first one, boutonimprimergrise undefined if it's set true in service , don't understand why because other 1 true...

i logged found nothing, if have idea you're welcomed :)

thanks

a couple things:

i typically define variables within service private unless need them not reason, , other thing use typescript define boutonimprimergrise variable behaviorsubject. (repeat both declarations)

private boutonimprimergrise: behaviorsubject<boolean> = new behaviorsubject<boolean>(true); boutonimprimergrisechanged$ = this.boutonimprimergrise.asobservable();