Schema_sample.re

<SignUpForm
  schema=[
    (`password, Required),
    (`email, Required),
    (
      `confirmPassword,
      Custom(
        values =>
          values.confirmPassword !== values.password ?
            Some("Passwords don't match") : None,
      ),
    ),
  ]>
  ...(_reform => ReasonReact.nullElement)
</SignUpForm>;