var args = process.argv.splice(process.execArgv.length + 2);
if(args.length != 1) {
    console.log('invalid argument length');
    process.exit(1);
}

var request = require('request'),
    cheerio = require('cheerio'),
    events  = require('events'),
    path    = require('path'),
    fs      = require('fs');

function ensureDirectoryExistence(filePath) {
    var dirname = path.dirname(filePath);
    if (directoryExists(dirname)) {
      return true;
    }
    ensureDirectoryExistence(dirname);
    fs.mkdirSync(dirname);
}

function directoryExists(path) {
  try {
    return fs.statSync(path).isDirectory();
  }
  catch (err) {
    return false;
  }
}

var KMS = function(seriesURL) {
    this.seriesURL = seriesURL;
}

KMS.prototype = new events.EventEmitter;

KMS.prototype.getPage = function(pURL) {
    var self = this;
    var cNum = pURL.substring(pURL.lastIndexOf('c'), pURL.lastIndexOf('/'));
    var pNum = '1';
    if(pURL.slice(pURL.lastIndexOf('/')).length != 1) pNum = pURL.substring(pURL.lastIndexOf('/')+1, pURL.lastIndexOf('.'));
    request(pURL, function(error, response, body) {
        if(!error && response.statusCode == 200) {
            var $ = cheerio.load(body);
            var imgUrl = $('#image').attr('src');
            var filePath = cNum + '/p' + pNum + '.jpg';
            ensureDirectoryExistence(filePath);
            console.log('Getting Page: ' + filePath.slice(0, -4));
            request(imgUrl).pipe(fs.createWriteStream(filePath));

            if($('#image').parent().attr('href') != 'javascript:void(0);') self.emit('new page', $('#image').parent().attr('href'));
        } else {
            console.log('Eror: ' + error);
        }
    });
};

KMS.prototype.run = function() {
    var self = this;
    request(self.seriesURL, function(error, response, body) {
        if(!error && response.statusCode==200) {
            var $ = cheerio.load(body);

            $('.detail_list > ul:nth-child(3) > li').each(function(i, elm) {
            self.emit('new page', ($(this).children('span:first-child').children('a').attr('href')));
        });
        } else {
            console.log('Error: ' + error);
        }
    });
}

var kms = new KMS(args[0]);

kms.on('new page', kms.getPage);
kms.on('err page', kms.getPage);

kms.run();

node mhs.js http://www.mangahere.co/manga/gantz/

Error: undefined is not a valid uri or options object.
    at request (D:DocumentsDev WorkspacesJavaScriptMangaScrapernode_modulesrequestindex.js:46:11)
    at Request._callback (D:DocumentsDev WorkspacesJavaScriptMangaScrapermhs.js:49:5)
    at Request.self.callback (D:DocumentsDev WorkspacesJavaScriptMangaScrapernode_modulesrequestrequest.js:199:22)
    at emitTwo (events.js:87:13)
    at Request.emit (events.js:172:7)
    at Request.<anonymous> (D:DocumentsDev WorkspacesJavaScriptMangaScrapernode_modulesrequestrequest.js:1036:10)
    at emitOne (events.js:82:20)
    at Request.emit (events.js:169:7)
    at IncomingMessage.<anonymous> (D:DocumentsDev WorkspacesJavaScriptMangaScrapernode_modulesrequestrequest.js:963:12)
    at emitNone (events.js:72:20)