Nodejs Utililty Methods String Format

Date.prototype.format = function ( formatString) {
  var months = new Array("Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec");
  var yyyy = this.getFullYear();
  var yy = yyyy.toString().substring(2);
  var m = this.getMonth();
  var mm = m < 10 ? "0" + m : m;
  var mmm = months[m];
  var d = this.getDate();
  var dd = d < 10 ? "0" + d : d;
...

String.format = function() {
  var s = arguments[0];
  for (var i = 0; i < arguments.length - 1; i++) {       
    var reg = new RegExp("\\{" + i + "\\}", "gm");             
    s = s.replace(reg, arguments[i + 1]);
  return s;

String.prototype.format = function() {
    var args = arguments;
    return this.replace(/\{(\d+)\}/g, function (m, n) { return args[n]; });
};

String.prototype.format=function(){
  var a=arguments;
  return this.replace(/\{(\d+)\}/g,function(b,c){return a[c]})
};

String.prototype.format = function() {
  a = this;
  for (k in arguments) {
    a = a.replace("{" + k + "}", arguments[k]);
  return a;
};

String.prototype.format = function() {
  var args = arguments;
  return this.replace(/{(\d{1})}/g, function() {
    return new String(args[arguments[1]]);
  });
};

String.prototype.format=function(){
  if(0==arguments.length)
     return this;
  var t=arguments;
  return this.replace(/\{(\d+)\}/g,function(r,n){
     return void 0===t[n]?"{"+n+"}":t[n]})
};

String.prototype.format = function() {
    var newStr = this, i = 0;
    while (/%s/.test(newStr))
        newStr = newStr.replace("%s", arguments[i++])
    return newStr;

String.prototype.format = function() {
    var args = arguments;
    return this.replace(/\{(\d+)\}/g, function() {
        return args[arguments[1]];
    });
};

String.prototype.format = function()
    var args = arguments;
    return this.replace(/\{(\d+)\}/g,                
        function(m,i){
            return args[i];
        });