thl.js

var stream = require('stream');
var assert = require('assert');
var PassThrough = stream.PassThrough;

var src = new PassThrough({ objectMode: true });
var tx = new PassThrough({ objectMode: true });
var dest = new PassThrough({ objectMode: true });

dest.on('data', function(x) {
  console.log('%s %j', typeof x, x);
});

src.pipe(tx).pipe(dest);

var i = -1;
var int = setInterval(function() {
  console.error('interval', i);
  if (i > 10) {
    src.end();
    clearInterval(int);
  } else {
    src.write(i++);
  }
});