Gmail normalization to prevent free tier abuse

normalize.js

function normalizeGmailAddress(email) {
  // Convert to lowercase
  email = email.toLowerCase();
  
  // Split the email into local part and domain
  let [localPart, domain] = email.split('@');
  
  // If it's not a Gmail address, return the original email
  if (domain !== 'gmail.com' && domain !== 'googlemail.com') {
    return email;
  }
  
  // Remove all dots from the local part
  localPart = localPart.replace(/\./g, '');
  
  // Remove everything after '+' in the local part
  localPart = localPart.split('+')[0];
  
  // Normalize googlemail.com to gmail.com
  domain = 'gmail.com';
  
  // Reconstruct the normalized email
  return `${localPart}@${domain}`;
}

// Example usage:
const emails = [
  'example@gmail.com',
  'e.x.a.m.p.l.e@gmail.com',
  'example+1@gmail.com',
  'examp.l.e@googlemail.com',
  'e.xample+2@gmail.com'
];

emails.forEach(email => {
  console.log(`Original: ${email}`);
  console.log(`Normalized: ${normalizeGmailAddress(email)}`);
  console.log('---');
});