How to use the breeze-client.EntityState.Unchanged function in breeze-client

map(currentUser => {

            if (currentUser === null) {

              localStorage.removeItem("token"); // Invalid or expired token

              this.currentUser = this.createGuestAccount();

            } else {

              // Attach user and its role to entity manager
              this.currentUser = this.appEntityManager.createEntity("User", currentUser, EntityState.Unchanged) as User;
              this.appEntityManager.createEntity("UserRole", currentUser.Roles[0], EntityState.Unchanged);

            }

            this.currentUserChanged.next(this.currentUser);
          }));
      }

map(currentUser => {

            if (currentUser === null) {

              localStorage.removeItem("token"); // Invalid or expired token

              this.currentUser = this.createGuestAccount();

            } else {

              // Attach user and its role to entity manager
              this.currentUser = this.appEntityManager.createEntity("User", currentUser, EntityState.Unchanged) as User;
              this.appEntityManager.createEntity("UserRole", currentUser.Roles[0], EntityState.Unchanged);

            }

            this.currentUserChanged.next(this.currentUser);
          }));
      }

canDeactivate(): boolean {
        if (this.currentUser.entityAspect.entityState === EntityState.Unchanged) {
            return true;
        }

        if (confirm("Discard changes?")) {
            this.currentUser.entityAspect.rejectChanges();
            return true;
        } else {
            return false;
        }
    }