This package converts a Readable Stream into a Buffer, with just one Buffer allocation (excluding allocations done internally by the streams implementation).

This is lighter-weight choice than stream-to-array when the total stream length is known in advance. This whole package is 15 lines.

This module is used by WebTorrent.

npm install stream-with-known-length-to-buffer

var toBuffer = require('stream-with-known-length-to-buffer')

toBuffer(fs.createReadStream('file.txt'), 1000, function (err, buf) {
  if (err) return console.error(err.message)
  console.log(buf)
})

MIT. Copyright (c) Feross Aboukhadijeh.