Nodejs Utililty Methods String to Underscore

String.prototype.toUnderscore = function(){
  return this.charAt(0).toLowerCase() + this.substring(1).replace(/([A-Z])/g, function($1){return "_"+$1.toLowerCase();});
};
console.log(process.argv[2].toUnderscore());

String.prototype.toUnderscore = function(){
  return this.replace(/([A-Z])/g, function($1){return "_"+$1.toLowerCase();});
};

function getId(obj){
  return parseInt($(obj).attr('id').split("-").pop(), 10);
String.prototype.toUnderscore = function(){
  return this.replace(/([A-Z])/g, function($1){return "_"+$1.toLowerCase();});
};

String.prototype.toUnderscore = function() {
  return this.replace(/(^[A-Z])/, function(match) {
    return match.toLowerCase();
  }).replace(/([A-Z])/g, function(match){
    return "_" + match.toLowerCase();
  });
};

String.prototype.toUnderscore = function() {
  var str = this.replace(/[A-Z]/g, function(s) {
    return "_" + s.toLowerCase();
  });
  while (str.charAt(0) === '_') {
    str = str.slice(1);
  return str;
};
...

String.prototype.toUnderscore = function() {
  var str = this;
  var modified = '';
  for (var i = 0; i < str.length; i++) {
    if (isLower(str[i])) {
      modified += str[i];
    } else {
      if (str.length > i-1) {
        if (isLower(str[i-1])) {
...

String.prototype.underscore = function() {
  return this.replace(/([a-z\d])([A-Z]+)/g, '$1_$2').replace(/[-\s]+/g, '_').toLowerCase();
};

String.prototype.underscore = function() {
  return this.gsub(/::/, '/').gsub(/([A-Z]+)([A-Z][a-z])/,'#{1}_#{2}').gsub(/([a-z\d])([A-Z])/,'#{1}_#{2}').gsub(/-/,'_').toLowerCase();
};

String.prototype.underscore = function() {
  return this
    .replace(/::/g, '/')
    .replace(/([A-Z]+)([A-Z][a-z])/g, '$1_$2')
    .replace(/([a-z\d])([A-Z])/g, '$1_$2')
    .replace(/-/g, '_')
    .toLowerCase();
};

String.prototype.underscore = function() {
  return this.trim().toLowerCase().replace(/[\s]+/g, '_');