validateUSPhoneNumbers.js

// Validate US Telephone Numbers
// Return true if the passed string is a valid US phone number.
//
// The user may fill out the form field any way they choose as long as it is a
// valid US number. The following are examples of valid formats for US numbers
// (refer to the tests below for other variants):
//
// 555-555-5555   regex = /[0-9]{3}-[0-9]{3}-[0-9]{4}/g
// (555)555-5555  regex = /\([0-9]{3}\)[0-9]{3}-[0-9]{4}/g
// (555) 555-5555 regex = /\([0-9]{3}\)\s[0-9]{3}-[0-9]{4}/g
// 555 555 5555   regex = /[0-9]{3}\s[0-9]{3}\s[0-9]{4}/g
// 5555555555     regex = /[0-9]{3}[0-9]{3}[0-9]{4}/g
// 1 555 555 5555 regex = /1\s[0-9]{3}\s[0-9]{3}\s[0-9]{4}/g
//
// For this challenge you will be presented with a string such as 800-692-7753 or
// 8oo-six427676;laskdjf. Your job is to validate or reject the US phone number
// based on any combination of the formats provided above. The area code is
// required. If the country code is provided, you must confirm that the country
// code is 1. Return true if the string is a valid US phone number; otherwise
// return false.

// First passing attempt:
function telephoneCheck(str) {
  const tests = [
    /^[0-9]{3}-[0-9]{3}-[0-9]{4}$/,
    /^\([0-9]{3}\)[0-9]{3}-[0-9]{4}$/,
    /^\([0-9]{3}\)\s[0-9]{3}-[0-9]{4}$/,
    /^[0-9]{3}\s[0-9]{3}\s[0-9]{4}$/,
    /^[0-9]{3}[0-9]{3}[0-9]{4}$/,
    /^1\s[0-9]{3}\s[0-9]{3}\s[0-9]{4}$/,
    /^1\s[0-9]{3}-[0-9]{3}-[0-9]{4}$/,
    /^1\s\([0-9]{3}\)\s[0-9]{3}-[0-9]{4}$/,
    /^1\([0-9]{3}\)[0-9]{3}-[0-9]{4}$/,
  ];

  return tests.some(reg => reg.test(str));
}

// Tests:
// telephoneCheck("555-555-5555") should return a boolean.
// telephoneCheck("1 555-555-5555") should return true.
// telephoneCheck("1 (555) 555-5555") should return true.
// telephoneCheck("5555555555") should return true.
// telephoneCheck("555-555-5555") should return true.
// telephoneCheck("(555)555-5555") should return true.
// telephoneCheck("1(555)555-5555") should return true.
// telephoneCheck("555-5555") should return false.
// telephoneCheck("5555555") should return false.
// telephoneCheck("1 555)555-5555") should return false.
// telephoneCheck("1 555 555 5555") should return true.
// telephoneCheck("1 456 789 4444") should return true.
// telephoneCheck("123**&!!asdf#") should return false.
// telephoneCheck("55555555") should return false.
// telephoneCheck("(6505552368)") should return false
// telephoneCheck("2 (757) 622-7382") should return false.
// telephoneCheck("0 (757) 622-7382") should return false.
// telephoneCheck("-1 (757) 622-7382") should return false
// telephoneCheck("2 757 622-7382") should return false.
// telephoneCheck("10 (757) 622-7382") should return false.
// telephoneCheck("27576227382") should return false.
// telephoneCheck("(275)76227382") should return false.
// telephoneCheck("2(757)6227382") should return false.
// telephoneCheck("2(757)622-7382") should return false.
// telephoneCheck("555)-555-5555") should return false.
// telephoneCheck("(555-555-5555") should return false.
// telephoneCheck("(555)5(55?)-5555") should return false.