Create a blob from a web stream in Node.js

I am trying to pack a CAR file through ipfs-car (which uses web streams) and later send it in a request as a file but I'm not sure how to store it in a Blob after I have streamed in a WritableStream.

I have this piece of code

import { CAREncoderStream, createDirectoryEncoderStream } from 'ipfs-car'
import { WritableStream } from 'node:stream/web'

export const packCAR = async (files) => {
  const blockStream = createDirectoryEncoderStream(files)
  const carEncoderStream = new CAREncoderStream([])
  const outStream = new WritableStream()
  await blockStream.pipeThrough(carEncoderStream).pipeTo(outStream)
  const blob = new Blob(/* what do I put here? */)
}

I haven't found anyone doing this, I only saw how to convert Blob to a stream, so help would be appreciated :)

Store the content of the WritableStream into a Blob. This can be done by transforming the WritableStream into a ReadableStream, then converting it into an ArrayBuffer, and finally storing the ArrayBuffer into a Blob.

import { CAREncoderStream, createDirectoryEncoderStream } from 'ipfs-car'
import { WritableStream, ReadableStream } from 'node:stream/web'

export const packCAR = async (files) => {
  const blockStream = createDirectoryEncoderStream(files)
  const carEncoderStream = new CAREncoderStream([])
  const chunks = []
  const outStream = new WritableStream({
    write(chunk) {
      chunks.push(chunk)
    },
    close() {
      console.log('Stream is closed.')
    }
  })
  await blockStream.pipeThrough(carEncoderStream).pipeTo(outStream)
  const arrayBuffer = await new Blob(chunks).arrayBuffer()
  const blob = new Blob([arrayBuffer])
  return blob
}