This is now not really needed as node streams are now async iterators

co-stream-iterator

This library gives you an easy way to process data coming from a stream linearly and synchronously using co or koa.

var co = require('co');
var request = require('request');
var iterator = require('co-stream-iterator');

co(function*() {
  var chunk, encoding;
  var read = iterator(request('http://google.com'), {});

  while (data = yield read) {
    console.log('data', data.encoding, data.chunk.toString());
  }
}).then(console.log);

It's even nicer looking when using destructuring:

while ({encoding, chunk} = yield read) {
  console.log('data', encoding, chunk.toString());
}

All you do is pass in your readable stream and your options for the writable stream it creates under the hood. This makes object streams possible to work with as well. The while loop ends when the data stops flowing. This is triggered by the generator returning null.