http://www.freecodecamp.com/harshitanand 's solution for Bonfire: Validate US Telephone Numbers

bonfire-validate-us-telephone-numbers.js

// Bonfire: Validate US Telephone Numbers
// Author: @harshitanand
// Challenge: http://www.freecodecamp.com/challenges/bonfire-validate-us-telephone-numbers
// Learn to Code at Free Code Camp (www.freecodecamp.com)

function telephoneCheck(str) {
  // Good luck!
  var re = /^(?:(?:\+?1\s*(?:[.-]\s*)?)?(?:\(\s*([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9])\s*\)|([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9]))\s*(?:[.-]\s*)?)?([2-9]1[02-9]|[2-9][02-9]1|[2-9][02-9]{2})\s*(?:[.-]\s*)?([0-9]{4})$/;

  return re.test(str);
}



telephoneCheck("555-555-5555");