files-loader.js

function readTextFiles(file, callback, ctx) {

        ctx = ctx || this;

        if (typeof file === 'object') {
            var index = file.length;
            var response = [];
            for (var i = 0; i < file.length; i++) {
                (function (f, i) {
                    readTextFiles(f, function (resp) {
                        response.splice(i, 0, resp);
                        index--;
                        if (!index) {
                            callback.apply(ctx, response);
                        }
                    })
                })(file[i], i)
            }
            return;
        }

        var rawFile = new XMLHttpRequest();
        rawFile.overrideMimeType("application/json");
        rawFile.open("GET", file, true);
        rawFile.onreadystatechange = function () {
            if (rawFile.readyState === 4 && rawFile.status == "200") {
                callback(rawFile.responseText);
            }
        };
        rawFile.send(null);
    }

    readTextFiles([configFile, dataFile], function (configSource, dataSource) {
        var config = JSON.parse(configSource);
        var data = JSON.parse(dataSource);

        var Customizer = new ReactCustomizer(config, data);
        Customizer.render();
        Customizer.onSubmit = function (data) {

        };
    });