Facade duplex streams

gistfile1.js

//https://www.npmjs.com/package/duplexer

var duplexer = require("duplexer");
var through = require("through2");

function boostrap(fn){
  var input = noop(); // Just passes data through
  var output = noop(); // Just passed data through;
  
  input.once("data",function(chunk, encoding, cb){
    fn(chunk, encoding, function(err,stream){
      if(err) return cb(err);
      input.pipe(stream).pipe(output); // Wire the input and output to the new stream
    });
  });
  return duplexer(input, output);
}

function noop(){
  return through(function(chunk,encoding,cb){
    return cb(null, chunk);
  });
}