ES6 written, XMLHttpRequest wrapper for RxJS

rx5xmlhttpwrapper.js

class ApiRequest {
  observableRequest(url) {
    return Rx.Observable.fromPromise(this.__makeRequest(url, 'GET'));
  }
  
  __makeRequest(url, method) {
    return new Promise((resolve, reject) => {
      let xhr = new XMLHttpRequest();
      
      Rx.Observable
        .fromEvent(xhr, 'load')
        .map(ev => ev.target)
        .subscribe(req => {
          if (req.status >= 200 && req.status < 300) {
            resolve(req.response);
          } else {
            reject(req.statusText);
          }
        });
      
      Rx.Observable
        .fromEvent(xhr, 'error')
        .map(ev => ev.target)
        .subscribe(req => reject(req.statusText));
      
      xhr.open(method, url, true);
      xhr.send(null);
    });
  }
}

// Usage
new ApiRequest().observableRequest('http://pokeapi.co/api/v2/pokemon/1').subscribe(response => console.log(response));