Why is it so cumbersome to do really simple things in node, like reading records from a file one by one? In Perl, C, PHP, Java, whatever, you'd just run: while ( record = file.fetch() ) { /* do stuff with record */ }

gistfile1.js

/*jslint node: true*/
'use strict';
var fs = require('fs');
var csv = require('csv');
var async = require('async');

// note, io.listen(<port>) will create a http server for you
//var io = require('socket.io').listen(8901);

//io.sockets.on('connection', function (socket) {

//  console.log("On connection");

var handle = csv().from('day,temp\nMon,20\nTue,22\nWed,25\nThu,23', { columns: true });

handle.fetch = function(howMany) {
  var self = this;
  console.error('Starting the fetch at', self.indexThatsNotBroken);
  self.indexThatsNotBroken |= 0;
  var stopAt = self.indexThatsNotBroken + howMany;

  self
    .transform(
      function (record, index, callback) {
        console.error(self.indexThatsNotBroken, record);
        self.indexThatsNotBroken++;
        if (self.indexThatsNotBroken >= stopAt) { return; }
        process.nextTick(function () {
          callback();
        });
      },
      {parallel: 1}
    );
  console.error('Stopped the fetch at', self.indexThatsNotBroken);
};

async.series([
  function (callback) {
    console.error('Async series call #1');
    handle.fetch(2);
    callback(null, 1);
  },
  function (callback) {
    console.error('We are at', handle.indexThatsNotBroken);
    callback(null, 1);
  },
  function (callback) {
    console.error('Async series call #2');
    handle.fetch(2);
    console.error('We are at', handle.indexThatsNotBroken);
    callback(null, 1);
  },
  function (callback) {
    console.error('Async series call #3');
    handle
      .on("end", function () {
        console.error("done");  // doesn't happen
      });
    callback(null, 1);
  }
]);

i'm wondering the exact same thing, node appears to be importing entire large amounts of data before doing the next portion of execution