Convert From/To Binary/Decimal/Hexadecimal in JavaScript + Normalize binary option

baseConverter.js

/**
* Convert From/To Binary/Decimal/Hexadecimal in JavaScript
* https://gist.github.com/faisalman
*
* Copyright 2012, Faisalman <fyzlman@gmail.com>
* Licensed under The MIT License
* http://www.opensource.org/licenses/mit-license
*/

(function(){

    var convertBase = function (num) {
        this.from = function (baseFrom) {
            this.to = function (baseTo) {
                return parseInt(num, baseFrom).toString(baseTo);
            };
            return this;
        };
        return this;
    };
    
    function normalizeTo(n_bit,binary){  
        if (binary.length == n_bit) {       
            return binary;      
        } else {       
            var msb = "";      
            for (var i=0; i<(n_bit - binary.length); i++){ msb = msb+"0"; }       
            return msb+binary;
        }   
    }  
            
    // binary to decimal
    this.bin2dec = function (num) {
        return convertBase(num).from(2).to(10);
    };
    
    // binary to hexadecimal
    this.bin2hex = function (num) {
        return convertBase(num).from(2).to(16);
    };
    
    // binary to octal
    this.bin2oct = function (num) {
        return convertBase(num).from(2).to(8);
    };
    
    // decimal to binary
    this.dec2bin = function (num, n_bit) {
      if (typeof n_bit === 'undefined'){
        return convertBase(num).from(10).to(2);  
      } else {
        return normalizeTo(n_bit, convertBase(num).from(10).to(2));
      }
    };
        
    // decimal to hexadecimal
    this.dec2hex = function (num) {
        return convertBase(num).from(10).to(16);
    };

    // decimal to octal
    this.dec2octal = function (num) {
        return convertBase(num).from(10).to(8);
    };    
    
    // hexadecimal to binary
    this.hex2bin = function (num, n_bit) {
      if (typeof n_bit === 'undefined'){
        return convertBase(num).from(16).to(2);  
      } else {
        return normalizeTo(n_bit, convertBase(num).from(16).to(2));
      }
    };
    
    // hexadecimal to decimal
    this.hex2dec = function (num) {
        return convertBase(num).from(16).to(10);
    };
    
    // hexadecimal to octal
    this.hex2dec = function (num) {
        return convertBase(num).from(16).to(8);
    };
    
    return this;        
})();

/*
* Usage example:
* bin2dec('111'); // '7'
* dec2hex('42'); // '2a'
* hex2bin('f8'); // '11111000'
* dec2bin('22'); // '10110'
* dec2bin('3','5'); // '00011'
*/