invert-stream

<img src=https://secure.travis-ci.org/dominictarr/invert-stream.png?branch=master>

Create a pair of streams (A, B) such that A.write(X) -> B.emit('data', X) and B.write(X) -> A.emit('data', X)

var invert = require('invert-stream')

var inverted = invert()

in_steam.pipe(inverted.other).pipe(out_stream)

inverted.write(data_for_outstream)
inverted.on('data', data_from_in_stream)

why ?

this is useful for a couple of things.

• testing streams based stuff
• making flexible duplex stream apis

an invert-stream pair is like a tcp connection, but in-process and synchronous. It's way easier to test edge cases related to event order if you stuff works sync.

Also, it's useful making duplex streams, or multiple streams into one.

Example

  var spawn = require('child_process').spawn
  var invert = require('invert-stream')

  var ch = spawn(cmd, args)
  var inverted = invert()

  ch.stdout.pipe(inverted.other).pipe(ch.sdin)

  //now, we have just ONE stream: inverted

  //write to che ch's stdin
  inverted.write(data)

  //read from ch's stdout
  inverted.on('data', ...) 

License

MIT