Apparently this module is broken and not compatible with more recent versions of nodejs.
Do not use.
Creates a duplex stream
Taken from event-stream
duplex (writeStream, readStream)
Takes a writable stream and a readable stream and makes them appear as a readable writable stream.
It is assumed that the two streams are connected to each other in some way.
var cp = require('child_process') , duplex = require('duplexer') , grep = cp.exec('grep Stream') duplex(grep.stdin, grep.stdout)
npm install duplexer