Validate and Parse Email Addresses with Regex

function parseEmail(email) {
  const emailRegex = /^([a-zA-Z0-9._%+-]+)@([a-zA-Z0-9.-]+\.[a-zA-Z]{2,})$/;
  const match = emailRegex.exec(email);

  if (match) {
    return {
      isValid: true,
      username: match[1],
      domain: match[2]
    };
  } else {
    return {
      isValid: false
    };
  }
}

// Examples:
console.log(parseEmail("[email protected]"));
/*
{
  isValid: true,
  username: 'user.name+tag',
  domain: 'example.co.uk'
}
*/
console.log(parseEmail("invalid-email")); // { isValid: false }

How it works: This JavaScript snippet uses regex to both validate an email address and extract its username and domain parts. The pattern `^([a-zA-Z0-9._%+-]+)@([a-zA-Z0-9.-]+\.[a-zA-Z]{2,})$` uses two capture groups: the first for the part before the '@' (`username`), and the second for the part after the '@' (`domain`). The `exec()` method returns an array containing the full match and captured groups, allowing easy access to the parsed components. If no match is found, it returns `null`.