MangaHere - Page collector.js

if (typeof jQuery === "undefined" || parseFloat(jQuery.fn.jquery,10) < 1.8){
    throw new Error("jQuery v1.8+ must be loaded in the page for the script to work.")
}
var once = function(fn, context){
  var i=0;
  return function(){
    if (i === 0){
        i++;
        return fn.apply(context, arguments);
    }
    throw new Error("Callback has been already called!");
  };
};
var slice = [].slice;
var forever = function(fn, callback, args, context) {
  if (typeof args === "undefined" || args === null){
    args = [];
  }

  if (typeof args !== "object" || args.constructor !== Array){
    args = [args];
  }

  var i=0;
  var next = function(error){
    i++;
    if (error !== null || error !== undefined && error){
      return callback.apply(context, arguments)
    }
    var others = slice.call(arguments,1); // args to next function.
    return fn.apply(context, [once(next), i].concat(others))
  };

  return fn.apply(context, [once(next), i].concat(args))
};
var CHAPTERURL_REGEX = /(http:\/\/|http:\/\/www\.)(mangahere.co\/manga\/[^\/]+\/[^\/]+\/[^\/]+)(?:\/\d+\.html|\/)?$/;

var MangaHereURLParser = (function() {

  MangaHereURLParser.name = 'MangaHereURLParser';

  function MangaHereURLParser(baseURL) {
    this.template = null;
    this.template = this.getTemplate(baseURL);
    this.startPage = this.parse(baseURL);
  }

  MangaHereURLParser.prototype.parse = function(str) {
    var match;
    if (!CHAPTERURL_REGEX.test(str)) {
      throw new Error("ChapterURL doesn't match the format.");
    }
    match = CHAPTERURL_REGEX.exec(str);
    if (match[3] === void 0) match[3] = "1";
    return {
      href: "http://www." + match[2] + "/" + match[3] + ".html",
      index: parseInt(match[3], 10) - 1
    };
  };

  MangaHereURLParser.prototype.getTemplate = function(str) {
    var match;
    if (!CHAPTERURL_REGEX.test(str)) {
      throw new Error("ChapterURL doesn't match the format.");
    }
    match = CHAPTERURL_REGEX.exec(str);
    return "http://www." + match[2] + "/#{@}.html";
  };

  MangaHereURLParser.prototype.getPage = function(n) {
    return {
      index: n,
      href: this.template.replace(/#\{@\}/g, n + 1)
    };
  };

  return MangaHereURLParser;

})();

var urlParser = new MangaHereURLParser("http://www.mangahere.co/manga/ge_good_ending/v13/c136/"); // change url here.

var chapter = {name: null, length: null};
var pages = [];
forever(function(next, i, page) {
    $.get(page.href, function(body, status, xhr){
        var jQ = $.parseHTML(body, true);
        if (i===0){
            chapter.length = $(jQ).find("select[onchange='change_page(this)']").eq(0).children("option").length;
            console.log("Chapter length added.");
            chapter.name = $(jQ).find("#top_chapter_list>option:selected").text();
            console.log("Chapter name added.");
        }
        pages.push($(jQ).find("img#image").attr("src"));
        console.log("Page - " +( page.index + 1)+ " added.");
        if (page.index >= (chapter.length-1)){
            var error = new Error("End");
            error.code = 214;
            return next(error);
        }
        pages.push($(jQ).find("script+img").attr("src"));
        console.log("Page - " +( page.index + 2)+ " added.");
        if (page.index >= (chapter.length-2)){
            var error = new Error("End");
            error.code = 214;
            return next(error);
        }
        return next(null, urlParser.getPage(page.index+2));
    });
}, function(error){
    if (error.code === 214){
        return console.log("Finished gathering pages.");
    }
    return console.error(error);
} , urlParser.startPage)