isEmail function

String? isEmail(
  1. String? val
)

return an error message if value does not pass the validation validation requires val: not equal null, must contain @ char, must contain dot(".") and length must be more than 4 characters

Implementation

String? isEmail(String? val) {
  final RegExp reg =
      RegExp(r"^([a-zA-Z\d\.-]+)@([a-z\d-]+)\.([a-z]{2,8})(\.[a-z]{2,8})?$");

  return reg.hasMatch((val ?? "").trim()) ? null : "enter a valid email ";
}