Nodejs Utililty Methods String Format

String.prototype.format = function(args) {
    var result = this;
    if (arguments.length > 0) {    
        if (arguments.length == 1 && typeof (args) == "object") {
            for (var key in args) {
                if(args[key]!=undefined){
                    var reg = new RegExp("({" + key + "})", "g");
                    result = result.replace(reg, args[key]);
        else {
            for (var i = 0; i < arguments.length; i++) {
                if (arguments[i] != undefined) {
                    var reg = new RegExp("({[" + i + "]})", "g");
                    result = result.replace(reg, arguments[i]);
    return result;

String.prototype.format = function (args) {
    var result = this;
    if (arguments.length > 0) {
        if (arguments.length == 1 && typeof (args) == "object") {
            for (var key in args) {
                if (args[key] != undefined) {
                    var reg = new RegExp("({" + key + "})", "g");
                    result = result.replace(reg, args[key]);
        else {
            for (var i = 0; i < arguments.length; i++) {
                if (arguments[i] != undefined) {
                    var reg = new RegExp("({)" + i + "(})", "g");
                    result = result.replace(reg, arguments[i]);
    return result;

String.prototype.format = function(args) {
    var result = this;
    if (arguments.length > 0) {    
        if (arguments.length == 1 && typeof (args) == "object") {
            for (var key in args) {
                if(args[key]!=undefined){
                    var reg = new RegExp("({" + key + "})", "g");
                    result = result.replace(reg, args[key]);
        else {
            for (var i = 0; i < arguments.length; i++) {
                if (arguments[i] != undefined) {
                    var reg = new RegExp("({[" + i + "]})", "g");
                    result = result.replace(reg, arguments[i]);
    return result;

String.prototype.format = function(args){
  var str = this.toString(),
      result = str.match(/\$[0-9]+/gi),
      mapper = {};
  if(args.length < result.length)
    throw new Error("Index out of range.");
  for(var i = 0; i < result.length; i++){
    mapper[result[i]] = args[parseInt(result[i].replace("$", ""), 10)]
  for(var i = 0; i < result.length; i++){
    str = str.replace(result[i], mapper[result[i]]);
  return str; 
};

String.prototype.format = function(args) {
    var result = this;
    if (arguments.length > 0) {    
        if (arguments.length == 1 && typeof (args) == "object") {
            for (var key in args) {
                if(args[key]!=undefined){
                    var reg = new RegExp("({" + key + "})", "g");
                    result = result.replace(reg, args[key]);
        else {
            for (var i = 0; i < arguments.length; i++) {
                if (arguments[i] != undefined) {
                    var reg= new RegExp("({)" + i + "(})", "g");
                    result = result.replace(reg, arguments[i]);
    return result;

function valPhone(phoneNumber) {
    if (!/^(13[0-9]|14[0-9]|15[0-9]|18[0-9])\d{8}$/i.test(phoneNumber)) {
        return false;
    } else {
        return true;
String.prototype.format = function(args) {
    if (arguments.length>0) {
...

String.prototype.format = function (args) {
    var str = this;
    return str.replace(String.prototype.format.regex, function (item) {
        var intVal = parseInt(item.substring(1, item.length - 1));
        var replace;
        if (intVal >= 0) {
            replace = args[intVal];
        } else if (intVal === -1) {
            replace = "{";
...

'use strict';
String.prototype.format = function (args) {
    if (arguments.length>0) {
        var result = this;
        console.log(this)
        if (arguments.length ==1 && typeof(args)=="object") {
            for(var key in args){
                var reg = new RegExp ("({"+key+"})","g");
                result = result.replace(reg,args[key]);
...

String.prototype.format = function(args)
    var result = this;
    if (arguments.length > 0)
        var reg;
        if (arguments.length == 1 && typeof(args) == "object")
            for (var key in args)
...

String.prototype.format = function (args) {
    var newStr = this;
    for (var key in args) {
        newStr = newStr.replace('{' + key + '}', args[key]);
    return newStr;