Writing large files with Node.js

That’s how I finally did it. The idea behind is to create readable stream implementing ReadStream interface and then use pipe() method to pipe data to writable stream.

var fs = require('fs');
var writeStream = fs.createWriteStream('someFile.txt', { flags : 'w' });
var readStream = new MyReadStream();

readStream.pipe(writeStream);
writeStream.on('close', function () {
    console.log('All done!');
});

The example of MyReadStream class can be taken from mongoose QueryStream.