const checksumStream = require('checksum-stream')
const fs = require('fs')
const request = require('request')
 
let req = request.get('https://npm.im/checksum-stream')
req.on('response', function (res) {
  res.pipe(
    checksumStream({
      algorithm: 'sha256',
      digest: res.headers['etag'],
      size: res.headers['content-length']
    }).on('error', e => throw e)
  ).pipe(
    fs.createWriteStream('./checksum-stream.html')
  )
})