XMLHttpRequest wrapped in a promise

xhr-in-promise.js

// request('GET',url)
// .then(console.log.bind(console))
// .catch(console.error.bind(console));

var request = function (verb,url,data) {
  
  return new Promise(function (resolve,reject) {

    var stateChange = function (xhr) {
      request = xhr.target;
      if (request.readyState !== 4) {
        return
      }       

      if ([200,304].indexOf(request.status) === -1) {
        reject(request);
      } else {
        resolve(request.response);
      }
    };

    var request = new XMLHttpRequest();
    request.open(verb,url,true);
    request.withCredentials = true;
    request.onreadystatechange = stateChange;
    request.setRequestHeader("Content-Type", "application/json");
    request.setRequestHeader("Accept","application/json");
    request.send(JSON.stringify(data));
  });

};