changePassword(oldPassword, newPassword, callback) {
        return this.UserService.changePassword({id: this.currentUser._id}, oldPassword, newPassword)
            .toPromise()
            .then(() => {console.log("success"); safeCb(callback)(null)})
            .catch(err => {console.log("error"); safeCb(callback)(err)});
    }

  changePassword(): void {
    this.submitted = true;
    return this.AuthService.changePassword(this.oldPassword, this.password)
      .then(() => {
        // success message
      })
      .catch(err => {
        // incorrect password message
      });
  }