renie/Ajax

'use strict';

(function(root, ajax) {
    /*
    **    UMD BLOCK
    */    
    if (typeof define === 'function' && define.amd) {
        // AMD
        define([], ajax);
    } else if (typeof exports === 'object') {
        // Node, CommonJS-like
        module.exports = ajax();
    } else {
        // Browser globals (root is window)
        root.Ajax = ajax();
    }
}(window, function() {

    var Ajax = {};

    Ajax.Utils = {
        extend : function() {
            var extended = {}, argument;

            for(var key in arguments) {
                argument = arguments[key];
                for (var prop in argument)
                    if (Object.prototype.hasOwnProperty.call(argument, prop))
                        extended[prop] = argument[prop];
            }

            return extended;
        },

        parseData : function(response, dataType) {
            if (dataType !== "text"){
                try{
                    return JSON.parse(response);
                } catch(e) {
                    return response;        
                }
            } else {
                return response;
            }
        }
    };

    Ajax.call = function(options) {
        var ajax = new Ajax.Methods(options);

        ajax.createRequest();

        ajax.bindEvents();

        ajax.req.send(ajax.opt.data);
    };

    Ajax.setup = function(options) {
        var opt = Ajax.Utils.extend(Ajax.Methods.prototype.defaultOptions, options);

        Ajax.Methods.prototype.defaultOptions = opt;
        Ajax.Methods.prototype.setupExecuted = true;
    };

    Ajax.Methods = function(options) {
        if (this.urlIsEmpty(options))
            throw new ReferenceError('URL is missing. It should be passed by parameter to Ajax.call method or setted on Ajax.setup.');

        this.opt = Ajax.Utils.extend(this.defaultOptions, options);

        return this;
    };

    Ajax.Methods.prototype.defaultOptions = {
        method        : 'GET',
        data        : null,
        success        : function(){},
        error        : function(){},
        contentType : 'application/x-www-form-urlencoded; charset=UTF-8',
        headers        : {},
        context        : window
    };

    Ajax.Methods.prototype.urlIsEmpty = function(options) {
        return ((!options.url && !this.setupExecuted) || (this.setupExecuted && !this.defaultOptions.url));
    };

    Ajax.Methods.prototype.bindEvents = function() {
        this.req.onload        = this.loadListener.bind(this);
        this.req.onerror    = this.errorListener.bind(this);
    };

    Ajax.Methods.prototype.createRequest = function() {
        this.req = new XMLHttpRequest();
        this.req.open(this.opt.method, this.opt.url, true);
        this.setHeaders();
    };

    Ajax.Methods.prototype.setHeaders = function() {
        this.opt.headers['Content-Type'] = this.opt.contentType;

        for (var header in this.opt.headers)
            this.req.setRequestHeader(header, this.opt.headers[header]);
    };

    Ajax.Methods.prototype.loadListener = function() {
        if (this.req.status >= 200 && this.req.status < 400)
            this.opt.success.call(this.opt.context, Ajax.Utils.parseData(this.req.responseText, this.opt.dataType));
        else
            this.errorListener.call(this, new Error(this.req.statusText));
    };

    Ajax.Methods.prototype.errorListener = function(err) {
        this.opt.error.call(this.opt.context, err, this.req);
    };

    return Ajax;

}));