normalizeEmail function

String normalizeEmail(String email, [ Map<String, Object>? options ])

canonicalize an email address.

options is a Map which defaults to { lowercase: true }. With lowercase set to true, the local part of the email address is lowercased for all domains; the hostname is always lowercased and the local part of the email address is always lowercased for hosts that are known to be case-insensitive (currently only GMail). Normalization follows special rules for known providers: currently, GMail addresses have dots removed in the local part and are stripped of tags (e.g. [e-mail] becomes [e-mail]) and all @googlemail.com addresses are normalized to @gmail.com.

Implementation

String normalizeEmail(String email, [Map<String, Object>? options]) {
  options = merge(options, _defaultNormalizeEmailOptions);
  if (isEmail(email) == false) {
    return '';
  }

  final parts = email.split('@');
  parts[1] = parts[1].toLowerCase();

  if (options['lowercase'] == true) {
    parts[0] = parts[0].toLowerCase();
  }

  if (parts[1] == 'gmail.com' || parts[1] == 'googlemail.com') {
    if (options['lowercase'] == false) {
      parts[0] = parts[0].toLowerCase();
    }
    parts[0] = parts[0].replaceAll('.', '').split('+')[0];
    parts[1] = 'gmail.com';
  }
  return parts.join('@');
}