Validate phone number with JavaScript

Question

I found this code in some website, and it works perfectly. It validates that the phone number is in one of these formats:
(123) 456-7890 or 123-

Answer 1

Validate phone number + return formatted data

function validTel(str){
  str = str.replace(/[^0-9]/g, '');
  var l = str.length;
  if(l<10) return ['error', 'Tel number length < 10'];
  
  var tel = '', num = str.substr(-7),
      code = str.substr(-10, 3),
      coCode = '';
  if(l>10) {
    coCode = '+' + str.substr(0, (l-10) );
  }
  tel = coCode +' ('+ code +') '+ num;
  
  return ['succes', tel];
}

console.log(validTel('+1 [223] 123.45.67'));