nodejs-write-large-file.js

const fs = require('fs');
const {LoremIpsum} = require("lorem-ipsum");
const lorem = new LoremIpsum();
const ws = fs.createWriteStream('somefile.txt');
// https://nodejs.org/api/stream.html#stream_event_drain
// Write the data to the supplied writable stream one million times.
// Be attentive to back-pressure.
function writeOneMillionTimes(writer, data, encoding, callback) {
  let i = 1000000;
  write();
  function write() {
    let ok = true;
    do {
      i--;
      if (i === 0) {
        // Last time!
        writer.write(data, encoding, callback);
      } else {
        // See if we should continue, or wait.
        // Don't pass the callback, because we're not done yet.
        //ok = writer.write(lorem.generateWords(4) + '\n', encoding);
        ok = writer.write(i + data, encoding);
      }
    } while (i > 0 && ok);
    if (i > 0) {
      // Had to stop early!
      // Write some more once it drains.
      writer.once('drain', write);
    }
  }
}

writeOneMillionTimes(ws, 'test\n', 'utf8', () => {
  console.log('all done!');
})