How to: Check if the email is valid or not in Dart| Flutter By Example

This program checks how to validate the email address.

Dart provides a RegExp class for matching strings with regular expressions.

Below are the rules for a valid email address.

• An email consists of distinct parts: the sender’s name, the ’@’ symbol, and the domain name.

• Both the recipient and domain names may contain lowercase and uppercase letters.

• The domain name contains an extension separated by a dot (’.’).

• Special characters are allowed in the sender’s name.

• The sender’s name can be up to 64 characters long.

• The domain name can be up to 256 characters long.

  Valid emails include [email protected], while invalid ones are abc and abc@abc.

#Dart Email Validation Using Regular Expressions

This program checks email validation using regular expressions. RegExp(regularexpression).hasMatch(emailString) evaluates the email string with a regular expression and returns a boolean value.

Here’s an example program:

void main() {
  print(isEmailValid("ababc.com")); // false
  print(isEmailValid("[email protected]")); // true
  print(isEmailValid("abc@abc")); // false
}

bool isEmailValid(String email) {
  return RegExp(
          r'^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$')
      .hasMatch(email);
}

Output:

false
true
false

Similarly, you can add Dart extensions to the String class. Extensions add new features to existing libraries.

Here’s an example program demonstrating how to write an extension for string email validation:

void main() {
  print("ababc.com".isEmailValid()); // false
  print("[email protected]".isEmailValid()); // true
  print("abc@abc".isEmailValid()); // false
}

extension EmailValidation on String {
  bool isEmailValid() {
    return RegExp(
            r'^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$')
        .hasMatch(this);
  }
}

#Conclusion

In summary, we’ve learned how to validate whether an email address is valid or not in Dart and Flutter.