validateField static method

String? validateField(
  1. String? value, {
  2. String? field,
  3. int? length,
})

Implementation

static String? validateField(String? value, {String? field, int? length}) {
  if (value == null || value.isEmpty) {
    if (field != null) {
      if (length != null) {
        return "$field must be $length characters long";
      }
      return "Please input your $field";
    } else {
      if (length != null) {
        return "This field required $length characters long";
      }
      return "Please input required field";
    }
  }
  return null;
}