upload.ts

type ReqInit = {
  method?: 'PUT' | 'POST';
  headers?: HeadersInit;
  body: Blob | BufferSource | FormData | URLSearchParams | string;
  signal?: AbortSignal;
  onProgress?: (bytesLoaded: number, bytesTotal: number) => void;
};

export function upload(url: string, init: ReqInit) {
  const { signal, onProgress, body } = init;
  const method = init.method ?? 'POST';
  const requestHeaders = new Headers(init.headers);
  return new Promise<Response>((resolve, reject) => {
    const request = new XMLHttpRequest();
    request.open(method, url);
    request.responseType = 'blob';

    requestHeaders.forEach((value: string, key: string) => {
      request.setRequestHeader(key, value);
    });

    if (signal) {
      const onAbort = () => {
        request.abort();
        reject(new AbortError());
      };
      signal.addEventListener('abort', onAbort);
      request.addEventListener('load', () => {
        signal.removeEventListener('abort', onAbort);
      });
    }

    if (onProgress) {
      request.upload.addEventListener('progress', (event) => {
        if (event.lengthComputable) {
          onProgress(event.loaded, event.total);
        }
      });
    }

    request.addEventListener('load', () => {
      const { status, statusText } = request;
      const response = new Response(request.response, {
        status,
        statusText,
        headers: parseHeaders(request),
      });
      resolve(response);
    });

    request.send(body);
  });
}

function parseHeaders(request: XMLHttpRequest) {
  const headers = new Headers();
  const lines = request
    .getAllResponseHeaders()
    .trim()
    .split(/[\r\n]+/);
  for (const line of lines) {
    const key = line.split(':')[0] ?? '';
    const value = request.getResponseHeader(key) ?? '';
    headers.set(key, value);
  }
  return headers;
}

class AbortError extends Error {
  constructor() {
    // This matches that of Chromium
    const message = t('The user aborted a request.');
    super(message);
  }

  get name() {
    return this.constructor.name;
  }

  get [Symbol.toStringTag]() {
    return this.constructor.name;
  }
}