Telephone Number Validator: Return true if the passed string looks like a valid US phone number. The user may fill out the form field any way they choose as long as it has the format of 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 (555)555-5555 (555) 555…

phoneNumValidator.js

function telephoneCheck(str) {
  // Good luck!
  let regex = /^([1]\s?)?(\([0-9]{3}\)|[0-9]{3})(\s|-)?[0-9]{3}(\s|-)?[0-9]{4}$/g;
  return regex.test(str);
  
}

telephoneCheck("555-555-5555");
/*
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("(6054756961)")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.
*/