Wrapping streams with other streams

gistfile1.js

var Readable = require('stream').Readable;
var util = require('util');

var Incoming = module.exports = function (opt) {
  this.stream = opt.stream;
  Readable.call(this, opt);
};
util.inherits(Incoming, Readable);

Incoming.prototype._read = function(n) {
  var chunk = this.stream.read();
  if(chunk) {
    this.push(chunk);
  }
};

function Counter(opt) {
  Readable.call(this, opt);
  this._max = 10000;
  this._index = 1;
}
util.inherits(Counter, Readable);

Counter.prototype._read = function() {
  var i = this._index++;
  if( i > this._max)
  {
    this.push(null);
  } else {
    var str = '' + i;
    var buf = new Buffer(str, 'ascii');
    this.push(buf);
  }
};

var c = new Counter();
var i = new Incoming({stream: c});

i.on('data', function(data) { 
  console.log(data.toString());
});

i.on('end', function() {
  console.log('done');
});