如何在异步更新进度的同时，成功地将blob流复制到文件或文件流中？

// 创建一个空的文件或文件流
const file = new File([], 'filename.txt');

// 定义读取和写入数据块的大小
const chunkSize = 1024; // 1KB

// 定义复制进度的回调函数
function updateProgress(progress) {
  console.log(`Copying progress: ${progress}%`);
}

// 异步读取blob流的数据块，并将其写入文件或文件流中
function copyBlobToStream(blob, stream) {
  return new Promise((resolve, reject) => {
    const reader = new FileReader();
    const writer = stream.getWriter();

    let offset = 0;
    let totalBytesCopied = 0;

    function readNextChunk() {
      const chunk = blob.slice(offset, offset + chunkSize);
      reader.readAsArrayBuffer(chunk);
    }

    reader.onload = () => {
      const buffer = reader.result;
      const bytesCopied = buffer.byteLength;

      writer.write(buffer)
        .then(() => {
          offset += bytesCopied;
          totalBytesCopied += bytesCopied;

          const progress = Math.floor((totalBytesCopied / blob.size) * 100);
          updateProgress(progress);

          if (offset < blob.size) {
            readNextChunk();
          } else {
            writer.close();
            resolve();
          }
        })
        .catch((error) => {
          writer.abort();
          reject(error);
        });
    };

    reader.onerror = (error) => {
      writer.abort();
      reject(error);
    };

    readNextChunk();
  });
}

// 使用示例
const blob = new Blob(['Hello, World!'], { type: 'text/plain' });
const writableStream = new WritableStream();

copyBlobToStream(blob, writableStream)
  .then(() => {
    console.log('Blob copied successfully.');
    const file = writableStream.getWriter().closed;
    // 在这里可以使用复制后的文件或文件流进行进一步的处理
  })
  .catch((error) => {
    console.error('Failed to copy blob:', error);
  });