Nodejs Utililty Methods IP Address Format Check

String.prototype.ipv4Address = function() {
  return /^(([1-9]?\d|1\d\d|2[0-4]\d|25[0-5])(\.(?!$)|$)){4}$/.test(this);
};

String.prototype.ipv4Address = function() {
  return /^(([1-9]?\d|1\d\d|2[0-4]\d|25[0-5])(\.(?!$)|$)){4}$/.test(this);
};

String.prototype.ipv4Address = function() {
  var ipv4 = this;
  if(ipv4.trim().length!=ipv4.length) return false;
  var arr = ipv4.split('.');
  if(arr.length!=4) return false;
  for(var i=0; i<arr.length; i++){
    if(!(checkWhiteSpace(arr[i]) && checkLeadZero(arr[i]) && checkForNum(arr[i]))){
      return false;
  return true;
};
function checkWhiteSpace(str){
  return str.trim().length == str.length;
function checkLeadZero(str){
  if(str.length==1) return true;
  if(str.charAt(0)==0) return false;
  if(str.charAt(0)=='+') return false;
  else return true;
function checkForNum(str){
  var num = parseInt(str);
  if(num>=0 && num<=255) {
    return true;
  }else {
    return false;

String.prototype.ipv4Address=function(){
  var newArr = this.split('.');
  if(newArr.length !== 4){
    return false;
  var test1 = this.split('.').join('');
  var regexp = new RegExp("\\D+", "g");
  if(regexp.test(test1) === true){
    return false;
...