var csv = require('csv-streamify'),
    fs = require('fs')

var fstream = fs.createReadStream('/path/to/file'),
    parser = csv(options /* optional */, callback /* optional */)

// emits each line as a buffer or as a string representing an array of fields
parser.on('readable', function () {
  var line = parser.read()
  // do stuff with data as it comes in

  // current line number
  console.log(parser.lineNo)
})

// AND/OR
function callback(err, doc) {
  if (err) return handleErrorGracefully(err)

  // doc is an array of row arrays
  doc.forEach(function (row) { console.log(row) })
}

// now pump some data into it (and pipe it somewhere else)
fstream.pipe(parser).pipe(nirvana)

{
  delimiter: ',', // comma, semicolon, whatever
  newline: '\n', // newline character (use \r\n for CRLF files)
  quote: '"', // what's considered a quote
  empty: '', // empty fields are replaced by this,

  // if true, emit arrays instead of stringified arrays or buffers
  objectMode: false,

  // if set to true, uses first row as keys -> [ { column1: value1, column2: value2 }, ...]
  columns: false
}