normalizeEmail.js

import isEmail from './isEmail';
import merge from './util/merge';

const default_normalize_email_options = {
  // The following options apply to all email addresses
  // Lowercases the local part of the email address.
  // Please note this may violate RFC 5321 as per http://stackoverflow.com/a/9808332/192024).
  // The domain is always lowercased, as per RFC 1035
  all_lowercase: true,

  // The following conversions are specific to GMail
  // Lowercases the local part of the GMail address (known to be case-insensitive)
  gmail_lowercase: true,
  // Removes dots from the local part of the email address, as that's ignored by GMail
  gmail_remove_dots: true,
  // Removes the subaddress (e.g. "+foo") from the email address
  gmail_remove_subaddress: true,
  // Conversts the googlemail.com domain to gmail.com
  gmail_convert_googlemaildotcom: true,

  // The following conversions are specific to Outlook.com / Windows Live / Hotmail
  // Lowercases the local part of the Outlook.com address (known to be case-insensitive)
  outlookdotcom_lowercase: true,
  // Removes the subaddress (e.g. "+foo") from the email address
  outlookdotcom_remove_subaddress: true,

  // The following conversions are specific to Yahoo
  // Lowercases the local part of the Yahoo address (known to be case-insensitive)
  yahoo_lowercase: true,
  // Removes the subaddress (e.g. "-foo") from the email address
  yahoo_remove_subaddress: true,

  // The following conversions are specific to iCloud
  // Lowercases the local part of the iCloud address (known to be case-insensitive)
  icloud_lowercase: true,
  // Removes the subaddress (e.g. "+foo") from the email address
  icloud_remove_subaddress: true,
};

// List of domains used by iCloud
const icloud_domains = [
  'icloud.com',
  'me.com',
];

// List of domains used by Outlook.com and its predecessors
// This list is likely incomplete.
// Partial reference:
// https://blogs.office.com/2013/04/17/outlook-com-gets-two-step-verification-sign-in-by-alias-and-new-international-domains/
const outlookdotcom_domains = [
  'hotmail.at',
  'hotmail.be',
  'hotmail.ca',
  'hotmail.cl',
  'hotmail.co.il',
  'hotmail.co.nz',
  'hotmail.co.th',
  'hotmail.co.uk',
  'hotmail.com',
  'hotmail.com.ar',
  'hotmail.com.au',
  'hotmail.com.br',
  'hotmail.com.gr',
  'hotmail.com.mx',
  'hotmail.com.pe',
  'hotmail.com.tr',
  'hotmail.com.vn',
  'hotmail.cz',
  'hotmail.de',
  'hotmail.dk',
  'hotmail.es',
  'hotmail.fr',
  'hotmail.hu',
  'hotmail.id',
  'hotmail.ie',
  'hotmail.in',
  'hotmail.it',
  'hotmail.jp',
  'hotmail.kr',
  'hotmail.lv',
  'hotmail.my',
  'hotmail.ph',
  'hotmail.pt',
  'hotmail.sa',
  'hotmail.sg',
  'hotmail.sk',
  'live.be',
  'live.co.uk',
  'live.com',
  'live.com.ar',
  'live.com.mx',
  'live.de',
  'live.es',
  'live.eu',
  'live.fr',
  'live.it',
  'live.nl',
  'msn.com',
  'outlook.at',
  'outlook.be',
  'outlook.cl',
  'outlook.co.il',
  'outlook.co.nz',
  'outlook.co.th',
  'outlook.com',
  'outlook.com.ar',
  'outlook.com.au',
  'outlook.com.br',
  'outlook.com.gr',
  'outlook.com.pe',
  'outlook.com.tr',
  'outlook.com.vn',
  'outlook.cz',
  'outlook.de',
  'outlook.dk',
  'outlook.es',
  'outlook.fr',
  'outlook.hu',
  'outlook.id',
  'outlook.ie',
  'outlook.in',
  'outlook.it',
  'outlook.jp',
  'outlook.kr',
  'outlook.lv',
  'outlook.my',
  'outlook.ph',
  'outlook.pt',
  'outlook.sa',
  'outlook.sg',
  'outlook.sk',
  'passport.com',
];

// List of domains used by Yahoo Mail
// This list is likely incomplete
const yahoo_domains = [
  'rocketmail.com',
  'yahoo.ca',
  'yahoo.co.uk',
  'yahoo.com',
  'yahoo.de',
  'yahoo.fr',
  'yahoo.in',
  'yahoo.it',
  'ymail.com',
];

export default function normalizeEmail(email, options) {
  options = merge(options, default_normalize_email_options);

  if (!isEmail(email)) {
    return false;
  }
  const parts = email.split('@', 2);

  // The domain is always lowercased, as it's case-insensitive per RFC 1035
  parts[1] = parts[1].toLowerCase();

  if (parts[1] === 'gmail.com' || parts[1] === 'googlemail.com') {
    // Address is GMail
    if (options.gmail_remove_subaddress) {
      parts[0] = parts[0].split('+')[0];
    }
    if (options.gmail_remove_dots) {
      parts[0] = parts[0].replace(/\./g, '');
    }
    if (!parts[0].length) {
      return false;
    }
    if (options.all_lowercase || options.gmail_lowercase) {
      parts[0] = parts[0].toLowerCase();
    }
    parts[1] = options.gmail_convert_googlemaildotcom ? 'gmail.com' : parts[1];
  } else if (~icloud_domains.indexOf(parts[1])) {
    // Address is iCloud
    if (options.icloud_remove_subaddress) {
      parts[0] = parts[0].split('+')[0];
    }
    if (!parts[0].length) {
      return false;
    }
    if (options.all_lowercase || options.icloud_lowercase) {
      parts[0] = parts[0].toLowerCase();
    }
  } else if (~outlookdotcom_domains.indexOf(parts[1])) {
    // Address is Outlook.com
    if (options.outlookdotcom_remove_subaddress) {
      parts[0] = parts[0].split('+')[0];
    }
    if (!parts[0].length) {
      return false;
    }
    if (options.all_lowercase || options.outlookdotcom_lowercase) {
      parts[0] = parts[0].toLowerCase();
    }
  } else if (~yahoo_domains.indexOf(parts[1])) {
    // Address is Yahoo
    if (options.yahoo_remove_subaddress) {
      let components = parts[0].split('-');
      parts[0] = (components.length > 1) ? components.slice(0, -1).join('-') : components[0];
    }
    if (!parts[0].length) {
      return false;
    }
    if (options.all_lowercase || options.yahoo_lowercase) {
      parts[0] = parts[0].toLowerCase();
    }
  } else {
    // Any other address
    if (options.all_lowercase) {
      parts[0] = parts[0].toLowerCase();
    }
  }
  return parts.join('@');
}