Nodejs Utililty Methods String Sub String from Left

if(!String.prototype.left){
  String.prototype.left = function(cnt){
    return this.substr(0,cnt);
  };
if(!String.prototype.right){
  String.prototype.right = function(cnt){
    return this.substr(this.length - cnt,this.length);
  };
...

String.prototype.left = function(count) {
    if (count >= this.length) {
        return this.toString();
    }else {
        return this.slice(0, count);
};

String.prototype.left = function (count) {
    return this.substring(0, count);

String.prototype.left = function(count) {
    var result = "";
    var stringLength = this.length;
    if (count > stringLength) {
        count = stringLength;
    var i;
    for (i = 0; i < count; i += 1) {
        result += this[i];
...

String.prototype.left = function(count) {
    if (count > this.length) return this.toString();
    return this.substring(0, count);
};

String.prototype.left = function(i)
    if (this.length > i) return this.substr(0, i) + "...";
    return this;
};

String.prototype.left = function(n) {
  return this.substr(0,n)

String.prototype.left = function(n) {
  return this.substr(0,n);
};

String.prototype.left = function(n) {
    return this.slice(0, n);

String.prototype.left = function(num) {
  var result = '';
  for (var i = 0; i < num; i++) {
    result += this[i];
  };
  return result;