Efficiently write large files using Node.js

streams_basic_chunking.js

'use strict';

// this program will result in an "JavaScript heap out of memory"
const fs = require('fs');

const printer = function () {
  const fil = fs.createWriteStream('file');
  let i = 0;
  const MAX_LIM = 1e6;

  const writer = function () {
    let result = true;

    // Write to file until we get false as fil.write()'s
    // result
    while (i < MAX_LIM && result) {
      result = fil.write(`Hello man: ${i}\n`);

      // even if the result is false, our write has been probably
      // written to the buffer. A false value denotes that the our last
      // write has resulted in buffered data, crossing the highWaterMark.
      // So, we have to increment the count.
      i += 1;
    }

    // Add an event listener if the last write was not
    // successful
    if (i < MAX_LIM)
      fil.once('drain', writer);
  }

  return writer;
}

const printty = printer();
printty();