Can't compare fields?

[GameBear64]

It would be very useful for password and confirm password fields. Or for example, a field called salary and then a field called desiredSalary that has a minimum of the salary field.

You might mention fields like $fieldName or @fieldName.

Here is an example for the idea

{
  password: 'required|min:8',
  confirmPassword: 'required|equals:$password',
  salary: 'numeric',
  desiredSalary: 'numeric|min:$salary'
}