iron-ajax.js

function ajax(method, url, body, params, cb) {
    var ia = document.createElement('iron-ajax');
    ia.url = url;
    ia.method = method;
    var self = this;
    if (body) {
        var formData = new FormData();
        if (body) {
          for (var param in body) {
            if (typeof body[param] == 'object') {
                formData.append(param, JSON.stringify(body[param]));
            }
            else {
                formData.append(param, body[param]);
            }
          }
        }
        ia.body = formData;
    }
    ia.addEventListener('response', function (resp) {
      if (resp && resp.detail && resp.detail.response) {
          var theResponse;
          if (typeof resp.detail.response == 'string') {
              try {
                  var r = JSON.parse(resp.detail.response);
                  theResponse = r;
              }
              catch (e) {
                  theResponse = resp.detail.response;
              }
          }
          else {
              theResponse = resp.detail.response;
          }
          if (theResponse.error) {
              cb(resp.detail.response);
          }
          else {
            cb(null, resp.detail.response);
          }
      }
      else {
        var res = { error: true, msg: "Could not post data" };
        cb(res);
      }
    });
    ia.addEventListener('error', function (resp) {
        var res = { error: true, msg: "Could not post data -- got error response." };
        cb(res);
    });
    ia.generateRequest();
}