Nodejs Utililty Methods String to Binary Convert

String.prototype.toBin = function() {
  var st,i,j,d;
  var arr = [];
  var len = this.length;
  for (i = len; i>0; i--) {
     d = this.charCodeAt(i-1);
    for (j = 0; j < 8; j++) {
       arr[arr.length] = d%2;
      d = Math.floor(d/2);
...

String.prototype.toBinary = function() {
  for (var i = 1, j = this.length, $ = this.charCodeAt(0).toString(2); i<j; i++) $ += ' ' + this.charCodeAt(i).toString(2);
  return $;
};

String.prototype.toBinary = function(){
    var ret = '';
    for (var i = 0; i < this.length; i++) {
        ret += this.charCodeAt(i).toString(2);
    return ret;