929 Unique Email Addresses.js

/**
 * Every email consists of a local name and a domain name,
 * separated by the @ sign.
 * For example, in alice@leetcode.com, alice is the local
 * name, and leetcode.com is the domain name.
 * Besides lowercase letters, these emails may contain '.'s
 * or '+'s.
 * If you add periods ('.') between some characters in the
 * local name part of an email address, mail sent there will
 * be forwarded to the same address without dots in the
 * local name.  For example, "alice.z@leetcode.com" and
 * "alicez@leetcode.com" forward to the same email address.
 * (Note that this rule does not apply for domain names.)
 * If you add a plus ('+') in the local name, everything
 * after the first plus sign will be ignored. This allows
 * certain emails to be filtered, for example m.y+name@email.com
 * will be forwarded to my@email.com.  (Again, this rule does
 * not apply for domain names.)
 * It is possible to use both of these rules at the same time.
 * Given a list of emails, we send one email to each address
 * in the list.  How many different addresses actually
 * receive mails?
 */

/**
 * Example:
 * Input: ["test.email+alex@leetcode.com",
 * "test.e.mail+bob.cathy@leetcode.com","testemail+david@lee.tcode.com"]
 * Output: 2
 * Explanation: "testemail@leetcode.com" and
 * "testemail@lee.tcode.com" actually receive mails
 */

/**
 * @param {string[]} emails
 * @return {number}
 */
const numUniqueEmails = (emails) => {
  const res = []
  if (emails.length === 1) {
    return 1
  }
  emails.forEach((email) => {
    const remote = email.split('@')[1]
    let local = email.split('@')[0]
    local = local.split('+') ? local.split('+')[0] : local
    local = local.split('.').join('')
    res.push(`${local}@${remote}`)
  })
  return [...new Set(res)].length
}

console.log(numUniqueEmails([
  'test.email+alex@leetcode.com',
  'test.e.mail+bob.cathy@leetcode.com',
  'testemail+david@lee.tcode.com',
]))