strongloop/loopback

i use angular 8 as frontend... this is on the authentication service constructor

setRenewalInterval(exp:number,iat:number){
        interval(10000).pipe(takeUntil(this.stopInterval), tap(n=>{
            let jwtokenDuration = exp - iat
            let datenowsec = Date.now() / 1000
            let remaining = exp - datenowsec
            let remainingP = remaining / jwtokenDuration
            this.ls.log(['authentication'],'JWToken renewal interval; tokenDuration: '+jwtokenDuration+' remaining: '+remaining+' remainingP: '+remainingP)
            //this.renewJWToken method is launched from the interceptor!
            if( remainingP < 0.333 ){
                this.stopInterval.next()
                this.getNewJWToken()
                .subscribe(res => {
                    this.ls.log(['authentication'],'JW TOKEN RENEWED, res:',JSON.stringify(res))
                    if(res.JWToken && res.JWToken.length > 0) this.renewToken(res.JWToken)
                })
            }
        })).subscribe()
    }

and the interceptor:

@Injectable()
export class JwtInterceptor implements HttpInterceptor {
    isLogin=false
    constructor(
        private authenticationService: AuthenticationService,
        private ls:LoggingService
    ) { }

    intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        if(request.url.startsWith('http')) this.ls.log(['interceptors'],'request intercepted by JWT interceptor: ',JSON.stringify(request))
        if(request.url.endsWith('/users/login')) this.isLogin = true
        else this.isLogin = false
        // add authorization header with JWToken if available
        let currentUserJWToken = this.authenticationService.currentUserJWToken;
        if (currentUserJWToken) {
            request = request.clone({
                setHeaders: {
                    Authorization: `Bearer ${currentUserJWToken}`
                }
            });
        }
        //intercept response and renew JWToken if present
        return next.handle(request).pipe(
            map( event => {
                if (!this.isLogin && event instanceof HttpResponse && event.body && event.body.JWToken && event.body.JWToken.length > 0){
                    this.authenticationService.renewToken(event.body.JWToken)
                }
                this.ls.log(['interceptors'],'JWT interceptor handle event:',JSON.stringify(event))
                return event
            })
        )
    }
}