angular - subscribing to BeahviorSubject in app.component constructor only triggers on first app load -

using angular2 in ionic 3 project:

i need change menu in app.component based on user subscription plan. in order after login, have currentuser$ asobservable of behaviorsubject. code setup:

app.component.ts -> constructor:

    this._authprovider.currentuser$   .subscribe(currentuser => {     //this._accountsandsettings = accountsandsettings     triggered++;     console.log('triggered', triggered);     if (currentuser.license === "agency") {       this._isagency = true;     };           ._menucontroller       .enable(true);     this._rootpage = "maintabspage";   }, accountsandsettingserror => {     //display alertcontroller , call platform.ready()     this._rootpage = "authloginpage";   }); 

loginpage.ts - >login:

  private _login(): void { //check missing credentials if (this._loginform.invalid) {   //alert pop-up   let missingcredentialsalert =     ._alertcontroller     .create({       message: "some credentials missing",       buttons: [         {           text: "ok",           role: 'cancel'         }       ]     });   missingcredentialsalert.present();   //call login } else {   let loginloading =     ._loadingcontroller     .create({ content: "logging in ..." });   loginloading.present();   let loginrequestbody = {     email: this._loginform.value.email,     password: this._loginform.value.password   }       .authprovider     .login(loginrequestbody)     .subscribe(currentuser => {       loginloading.dismiss();               }, currentuser => {       loginloading.dismiss();       let alert =         ._alertcontroller         .create({           title: null,           message: currentuser.msg_id,           buttons: [             {               text: "ok"             }           ]         });       alert.present();     }); }; 

authprovider -> constructor:

  private _currentusersource: behaviorsubject<userinfo> = new behaviorsubject(null);   public updatedcurrentuser$ =     ._currentusersource     .asobservable(); 

authprovider -> login:

  public login(loginrequestbody): observable<object> { return   ._http   .post('/user/login', loginrequestbody)   .flatmap(response => {     return observable.frompromise(this._ionicstorage.set(this._keyforuserinfoinstorage, response.json().userandsettings).then(saveduserinfo => {               ._currentusersource         .next(saveduserinfo);       return saveduserinfo;     }));   })   .catch(loginerror => {     return observable.throw(loginerror);   });   }; end login 

after logging in agency user, expect page change maintabspage agency menu (_isagency used in *ngif show additional menu items). happening after login page remains on login, , subscribe not triggered in app.component constructor.