Node.js ReadableStream: what is chunk size?

Question

Let's look at the following code snippet:

const fs = require('fs');
const server = require('http').createServer();

server.on('request', (req, res) => {
  const src = fs.createReadStream('./big.file');
  src.pipe(res);
});

server.listen(8000);

fs.createReadStream divides the content of big.file to chunks and reads the file "chunk after chunk".

My question is what is the size of every chunk, where it's defined and how I can change the chunk size?

Answer 1

here is how to change the chunk size

var rs = fs.createReadStream('/foo/bar', { highWaterMark: 128 * 1024 });

Answer 2

Check the documentation for createReadStream here.

It takes in an options object as its second parameter.

highWaterMark is the option that you are looking for, and it defaults to 64 * 1024.