Loops over a file containing one JSON entry per line and prints out the created_at value . This gist shows the original coffeescript and the generated JavaScript

print_times.coffee

fs = require 'fs'

unless process.argv.length > 2
    console.error "Usage: print_times <file>"
    process.exit -1

fileName = process.argv[2]

String::endsWith = (ch) ->
    return @length - 1 == @lastIndexOf(ch)

list_to_json = (list) ->
    (JSON.parse l for l in list)

fs.readFile fileName, 'utf-8', (err, data) ->
    throw err if err

    lines = data.split '\n'
    lines = lines[0...lines.length - 1]
    chomped = (line.trim() for line in lines)
    fulllines = (line for line in chomped when line.endsWith "}")

    tweets = list_to_json(fulllines)
    console.log "Read #{ tweets.length } tweets"

    times = (tweet.created_at for tweet in tweets when tweet.created_at?)
    console.log time for time in times

    null

print_times.js

(function() {
  var fileName, fs, list_to_json, parse_tweet;

  fs = require('fs');

  if (!(process.argv.length > 2)) {
    console.error("Usage: print_times <file>");
    process.exit(-1);
  }

  fileName = process.argv[2];

  String.prototype.endsWith = function(ch) {
    return this.length - 1 === this.lastIndexOf(ch);
  };

  list_to_json = function(list) {
    var l;
    return [
      (function() {
        var _i, _len, _results;
        _results = [];
        for (_i = 0, _len = list.length; _i < _len; _i++) {
          l = list[_i];
          _results.push(JSON.parse(l));
        }
        return _results;
      })()
    ];
  };

  parse_tweet = function(line, ix) {
    return JSON.parse(line);
  };

  fs.readFile(fileName, 'utf-8', function(err, data) {
    var chomped, fulllines, line, lines, time, times, tweet, tweets, _i, _len;
    if (err) throw err;
    lines = data.split('\n');
    lines = lines.slice(0, (lines.length - 1));
    chomped = (function() {
      var _i, _len, _results;
      _results = [];
      for (_i = 0, _len = lines.length; _i < _len; _i++) {
        line = lines[_i];
        _results.push(line.trim());
      }
      return _results;
    })();
    fulllines = (function() {
      var _i, _len, _results;
      _results = [];
      for (_i = 0, _len = chomped.length; _i < _len; _i++) {
        line = chomped[_i];
        if (line.endsWith("}")) _results.push(line);
      }
      return _results;
    })();
    console.log("" + fulllines.length + " fl");
    tweets = list_to_json(fulllines);
    console.log("Read " + tweets.length + " tweets");
    times = (function() {
      var _i, _len, _results;
      _results = [];
      for (_i = 0, _len = tweets.length; _i < _len; _i++) {
        tweet = tweets[_i];
        if (tweet.created_at != null) _results.push(tweet.created_at);
      }
      return _results;
    })();
    for (_i = 0, _len = times.length; _i < _len; _i++) {
      time = times[_i];
      console.log(time);
    }
    return null;
  });

}).call(this);