Property 'token' does not exist on type 'Users'

Question

I am working on Authentication in my project, but these two errors popped up and I am not sure what it means. This is the code in the jwt.interceptor.ts, with the errors as comments:

import { Injectable } from '@angular/core';
import { HttpRequest, HttpHandler, HttpEvent, HttpInterceptor } from '@angular/common/http';
import { Observable } from 'rxjs';

import { AuthenticationService } from './authentication.service';

@Injectable()
export class JwtInterceptor implements HttpInterceptor {
    constructor(private authenticationService: AuthenticationService) { }

    intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        // add authorization header with jwt token if available
        let currentUser = this.authenticationService.currentUserValue;
        if (currentUser && currentUser.token) {
            //                         ~~~~~
            // error TS2339: Property 'token' does not exist on type 'Users'
            request = request.clone({
                setHeaders: {
                    Authorization: `Bearer ${currentUser.token}`
                    //                                   ~~~~~
                    // error TS2339: Property 'token' does not exist on type 'Users'
                }
            });
        }

        return next.handle(request);
    }
}

And this is the function in the token.service.ts that corresponds to another error:

  isValid() {
    const token = this.get();
    if (token) {
      const payload = this.payload(token);
      if (payload) {
        return Object.values(this.iss).indexOf(payload.iss) > -1 ? true : false;
        //            ~~~~~~
        // error TS2339: Property 'values' does not exist on type 'ObjectConstructor'.
      }
    }
    return false;
  }