Exploring Node.js streams

streams.js

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

server.on('request', (req, res) => {
  /**
   * We basically put the whole big.file (~400mb) content in memory before we write it
   * out to the response object. This is very inefficient.
   * memory used: ~430mb
   */
  // fs.readFile('./big.file', (err, data) => {
  //   if (err) throw err;
  //   res.end(data);
  // });
  /**
   * The HTTP response object (res in the code above) is also a writable stream.
   * This means if we have a readable stream that represents the content of big.file,
   * we can just pipe those two on each other and achieve mostly the same result without
   * consuming ~400 MB of memory. Node’s fs module can give us a readable stream for any
   * file using the createReadStream method. We can pipe that to the response object.
   * memory used: ~40mb
   */
  const src = fs.createReadStream('./big.file');
  src.pipe(res);
});
server.listen(8000);