Parsing huge logfiles in Node.js - read in line-by-line.js

// Parsing huge logfiles in Node.js - read in line-by-line
//
// http://stackoverflow.com/a/23695940/4989460
//
// npm install event-stream --save
//

var fs = require('fs')
    , util = require('util')
    , stream = require('stream')
    , es = require('event-stream');

var lineNr = 1;

var s = fs.createReadStream('very-large-file.csv')
    .pipe(es.split())
    .pipe(es.mapSync(function(line){

        // pause the readstream
        s.pause();

        lineNr += 1;

        // process line here and call s.resume() when rdy
        logMemoryUsage(lineNr);

        // resume the readstream
        s.resume();
    })
    .on('error', function(){
        console.log('Error while reading file.');
    })
    .on('end', function(){
        console.log('Read entirefile.')
    })
);