[Angular2 Form] Check password match

<h1>password match</h1>
<form novalidate autocomplete="off" [formGroup]="signupForm">
  <div class="form-field">
    <label>Password:</label>
    <input type="text" formControlName="password" [(ngModel)]="signup.password" name="password">
  </div>
  <div class="form-field">
    <label>Confirm Password: </label>
    <input type="text" formControlName="confirm" [(ngModel)]="signup.confirm" name="confrim"></div>
</form>

    this.signupForm = fb.group({
      password: [
        '',
        Validators.required
      ],
      confirm: [
        '',
        [
          Validators.required,
          confirmPasswords.bind(undefined, this.signup)
        ]
      ]
    });

export function confirmPasswords(passwords, confirm) {
  const valid = passwords.password&& passwords.password === confirm.value;
  return valid ? null : {
    confirmPassword: {
      valid: false,
      message: "Two passwrods are not the same"
    }
  };
}