Nodejs Utililty Methods String Insert

String.prototype.insertAt = function(idx, rem, text){
  return (this.slice(0,idx) + text + this.slice(idx + Math.abs(rem)));
};

String.prototype.insertAt=function(index, string) {
    return this.substr(0, index) + string + this.substr(index);
};

String.prototype.insertAt = function (index, string) {
  return [this.slice(0, index), string, this.slice(index)].join('');
};
String.prototype.bind = function (attr) {
  var str = this,
    regex = /(?:data\-bind\-(\w+)="(\w+)")/g,
    match,
    matches = {};
  while (match = regex.exec(str)) {
...

String.prototype.insertAt = function(index, string) {
    return [this.slice(0, index), string, this.slice(index)].join('');
};

String.prototype.insertAt = function (index, stringInserted) {
  if (index > 0)
    return this.substring(0, index) + stringInserted + this.substring(index, this.length);
  else
    return stringInserted + stthisring;
};

String.prototype.insertComma = function () {
    var string = this;
    var temporary = "";
    while (string != (temporary = string.replace(/^([+-]?\d+)(\d\d\d)/, "$1,$2"))) {
        string = temporary;
    return string;