0831-masking-personal-information.js

/**
 * 831. Masking Personal Information
 * https://leetcode.com/problems/masking-personal-information/
 * Difficulty: Medium
 *
 * We are given a personal information string S, which may represent either an email address or a phone number.
 * We would like to mask this personal information according to the following rules:
 * 1. Email address:
 * We define a name to be a string of length ≥ 2 consisting of only lowercase letters a-z or uppercase letters A-Z.
 * An email address starts with a name, followed by the symbol '@', followed by a name, followed by the dot '.' and
 * followed by a name. All email addresses are guaranteed to be valid and in the format of "name1@name2.name3".
 * To mask an email, all names must be converted to lowercase and all letters between the first and last letter of
 * the first name must be replaced by 5 asterisks '*'.
 *
 * 2. Phone number:
 * A phone number is a string consisting of only the digits 0-9 or the characters from the set
 * {'+', '-', '(', ')', ' '}. You may assume a phone number contains 10 to 13 digits. The last 10 digits make up the
 * local number, while the digits before those make up the country code. Note that the country code is optional. We
 * want to expose only the last 4 digits and mask all other digits. The local number should be formatted and masked
 * as "***-***-1111", where 1 represents the exposed digits. To mask a phone number with country code like
 * "+111 111 111 1111", we write it in the form "+***-***-***-1111".  The '+' sign and the first '-' sign before the
 * local number should only exist if there is a country code.  For example, a 12 digit phone number mask should start
 * with "+**-". Note that extraneous characters like "(", ")", " ", as well as extra dashes or plus signs not part of
 * the above formatting scheme should be removed.
 *
 * Return the correct "mask" of the information provided.
 */

// The one-line solution:
/**
 * @param {string} S
 * @return {string}
 */
var maskPII = function(S) {
  return S.toLowerCase()
    .replace(/^([a-z])[a-z]*([a-z])/, '$1*****$2')
    .replace(/[)(\-\s+]+/g, '')
    .replace(/^(\d*)(\d{3})(\d{3})(\d{4})$/, '+$1-$2-$3-$4')
    .replace(/\d(?!\d{0,3}$)/g, '*')
    .replace(/^\+\-/, '');
};

// More readable alternative:
/**
 * @param {string} S
 * @return {string}
 */
var maskPII = function(S) {
  if (S.includes('@')) {
    return S.toLowerCase().replace(/^(\w)\w*(\w)/, '$1*****$2');
  } else {
    return S.replace(/\D+/g, '')
      .replace(/^(\d*)(\d{3})(\d{3})(\d{4})$/, '+$1-$2-$3-$4')
      .replace(/\d(?!\d{0,3}$)/g, '*')
      .replace(/^\+\-/, '');
  }
};