Get a Promise out of an XHR

send.js

function send(
  url,
  { method = 'GET', data, headers = {}, user, password, ...opts } = {}
) {
  const xhr = new XMLHttpRequest();
  const promise = new Promise((resolve, reject) => {
    xhr.open(method, url, true, user, password);
    xhr.addEventListener('load', resolve);
    xhr.addEventListener('error', reject);
    xhr.addEventListener('abort', reject);
    xhr.addEventListener('timeout', reject);
    Object.entries(headers).forEach(([name, value]) =>
      xhr.setRequestHeader(name, value)
    );
    Object.entries(opts).forEach(([name, value]) => {
      xhr[name] = value;
    });
    xhr.send(data);
  });
  // Expose the xhr to allow abortion and listening to other events
  promise.xhr = xhr;
  return promise;
}

Hello, can you add POST to a XMLHttpRequest with a Promise?

Probably seeing this too late, but you can use the method argument of the function to pick which HTTP method to use when sending the request :)