Nodejs Utililty Methods String Replace

String.prototype.replaceAt = function(index, stringInserted) {
    return this.substr(0, index) + stringInserted + this.substr(index+stringInserted.length);
};

String.prototype.replaceAt = function(index, text){
    return this.substr(0, index) + text + this.substr(index + text.length);

String.prototype.replaceAt = function(index, value) {
    var str1 = this.slice(0, index);
    var str2 = this.slice(index+1);
    return str1 + value + str2;
};

String.prototype.replaceAt = function(startIndex, endIndex, value) {
  var beforeIndex = this.substr(0, startIndex);
  var afterIndex = this.substr(endIndex);
  return beforeIndex + value + afterIndex;
};

var text = '',
    inputMessage = 'Enter a text:',
    replacedText,
    nonBreakingWhiteSpace = '&nbsp';
String.prototype.replace = function (index, subString) {
    var replacedText = this.substr(0, index) + subString + this.substr(index + 1);
    return replacedText;
function replaceNonBreakingWhiteSpaces(text) {
...

String.prototype.replaceAt_with_size = function(index, text, size){
    return this.substr(0, index) + text + this.substr(index + size);

String.prototype.replaceBorderWidth = function(width) {
  if ( ! width) width = 1;
  return this.replace(/^[0-9]+([a-z]+)?( [a-zA-Z]+ .+)$/, width+'px$2');
};

String.prototype.replaceChars = function(character, replacement){
    var str = this;
    var a;
    var b;
    for(var i=0; i < str.length; i++){
        if(str.charAt(i) == character){
            a = str.substr(0, i) + replacement;
            b = str.substr(i + 1);
            str = a + b;
...

String.prototype.replaceDateFormat=function(){
    return this.replace(/-/g,'/');

String.prototype.replaceEntities = function () {
  return this.replace(/\s*<br>\s*/g, '\n').replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/ +(?= )/g, '');
};