Node.js-将可写流分配给变量

Question

As in below code, I can write base64 encoded stream into a file but I want to assign the base64 encoded string to a variable rather than creating a file so that I can use it for the purpose I want. How can I assign response.pipe(base64.encode()); to a variable as base64 encoded string ? I am using base64-stream to encode incoming stream.

const request = xero.call('GET', `/Invoices/${invoiceId}`);
  request.setHeader('Accept', 'application/pdf');

  request.on('response', async (response) => {
    const data = response.pipe(base64.encode());
    const file = fs.createWriteStream(`${invoiceId}.txt`);
    data.pipe(file);
  });
  request.end();

Answer 1

To store the contents of the stream as a string you need to concatenate the base64 stream and then store that buffer as a variable. For that I like to use concat-stream .

keep the stream around with const data = response.pipe(base64.encode());

but then

data.pipe(concat(buf => {
  const str = buf.toString('base64')
})