Twitter Streaming API with Node.js Request module

twitter_filter.js

var request = require('request');

function filter(options, callback){
  var params = {
    uri: "https://stream.twitter.com/1/statuses/filter.json",
  }
  if (typeof options['oauth'] !== 'undefined'){
    params.oauth = options.oauth;
    delete options.oauth;
  }
  else if (typeof options['basic'] !== 'undefined') {
    params.uri = params.uri.replace(/^https?:\/\//,
       'https://' + options.basic.username + ':' + options.basic.password + '@'
    );
    delete options.basic;
  }
  params.form = options;
  
  var req = request.post(params, function(err, response, body){
    if (err) console.error(err);
  });
  // The callback for request.post is called when the response returns so you
  // have to save the post object and add a callback for the data event.
  req.on('data', function(buffer){
    callback(JSON.parse(buffer.toString()));
  });
};

filter({ basic: { username: '', password: '' }, track: 'new hampshire' }, 
  function(tweet) { console.log(tweet); }
);

4 years on and still really helpful - thanks.
Here's an updated version for the new Twitter API
See the repository readme for documentation :)