Handwritten native ajax

app.Ajax              = function (options) {
  var XHR    = function (options) {
    var params  = {
      methods: "GET",
      url    : "",
      timeout: 3000,
      success: undefined,
      err    : undefined,
    };
    params      = Object.assign(params, options);
    var xhrHttp = new XMLHttpRequest();
    xhrHttp.open(params.methods, params.url);
    xhrHttp.timeout = params.timeout;
    xhrHttp.send();
    xhrHttp.onreadystatechange = function () {
      if (xhrHttp.readyState === 4) {
        if (xhrHttp.status === 200) {
          if (app.isFunction(params.success)) {
            params.success(xhrHttp.responseText);
          }
        } else {
          if (app.isFunction(params.fail)) {
            params.fail(xhrHttp.responseText);
          }
        }
      }
    };
    xhrHttp.onerror            = function (e) {
      if (app.isFunction(params.fail)) {
        params.fail(e);
      }
    };
    xhrHttp.ontimeout          = function (e) {
      if (app.isFunction(params.fail)) {
        params.fail(e);
      }
    };
    return xhrHttp;
  };
  XHR.cancel = function (cache) {
    cache[0].abort();
    for (var c = 0; c < cache.length; c++) {
      var xhr = cache[c];
      xhr.abort();
    }
    return this;
  };
  return {
    fetch : XHR,
    cancel: XHR.cancel
  };

};