Return error using custom fetch

[villenams]

I am using a custom fetch function to monitor the upload of a file, everything runs fine, but at the end of the process it always returns an error message.
Maybe I should implement my custom fetch in a different way?

const graphql = newGraphqlClient({
  fetch: (
  url,
  options: {
    body?: FormData;
    method?: string;
    headers?: Record<string, string>;
  } = {}
) => {
  return new Promise((resolve, reject) => {
    const xhr = new XMLHttpRequest();

    xhr.open(options.method || "POST", url);

    for (const o in options.headers || {}) {
      xhr.setRequestHeader(o, options.headers[o]);
    }

    xhr.onload = (event) => {
      return resolve({
        ok: true,
        text: () => Promise.resolve(event.target),
        json: () => Promise.resolve(event.target)
      });
    };

    xhr.onerror = reject;

    if (xhr.upload) {
      xhr.upload.onprogress = (event) => {
        console.log(event.loaded / event.total) * 100);
      };
    }

    xhr.send(options.body);
  });
}
});

[jasonkuhrt]

File uploads were removed in #501