XMLHttpRequest with blob data in NW.js

I have written a REST utility method for a client side NW.js application I am working on. I extended the implementation from an example I found on stack overflow, although I can't seem to find it right now.

Here is the logic:

_makeRequest = function(method, url, params, headers, responseType) {
    params = params || null;
    headers = headers || null;
    responseType = responseType || null;

    return new Promise(function (resolve, reject) {
      // We'll need to stringify if we've been given an object
      // If we have a string, ArrayBuffer, Blob, or File, this is skipped.
      if (params && (typeof params === 'object') && !(
          params instanceof ArrayBuffer ||
          params instanceof Blob ||
          params instanceof File
        )) {
        params = Object.keys(params).map(function (key) {
          return encodeURIComponent(key) + '=' + encodeURIComponent( _resolveDatasetNamespace( params[key] ) );
        }).join('&');
      }

      var xhr = new XMLHttpRequest();
      xhr.responseType = (responseType) ? responseType : "";
      xhr.open(method, (method === "GET" && params) ? url + "?" + params : url);
      xhr.onload = function () {
        if (this.status >= 200 && this.status < 300) {
          resolve(xhr.response);
        } else {
          reject({
            status: this.status,
            statusText: xhr.statusText
          });
        }
      };
      xhr.onerror = function () {
        reject({
          status: this.status,
          statusText: xhr.statusText
        });
      };
      if (headers) {
        Object.keys(headers).forEach(function (key) {
          xhr.setRequestHeader(key, headers[key]);
        });
      }
      xhr.send(params);
    });
  };

Overall the method works great, but I noticed that I would trigger the oh so unhelpful onerror callback when I tried to send Blob data.

I verified with MDN that my logic looked sane. Then I tested in the browser javascript console to find the logic worked just fine there.

I finally came across this post and realized the implementation running in the node.js based NW.js framework must be at fault. I totally didn't consider the fact that node.js didn't natively contain an implementation of XMLHttpRequest, so I'm assuming that this is provided by CEF in NW.js.

I verified that instanceof Blob returned false in my NW.js application but true in the browser.

I really wanted to keep this implementation based on browser technology as it is both portable and a breeze to sanity check in a browser. I noticed other issues on the NW.js github so I assume it is intended to be used with the framework.

I know I could fall back to the node.js standard way of handling this problem, but I am curious if there is a way to resolve this issue.

I also noticed this suggestion for a fully node based application conversion.

Any other suggestions?