A binary stream multiplexer
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A binary stream multiplexer. Stream multiple streams of binary data over a single binary stream. Like mux-demux but faster since it only works with binary streams.



var multiplex = require('multiplex')([options], [onStream])

Returns a new multiplexer. You can use this to create sub-streams. All data written to sub-streams will be emitted through this. If you pipe a multiplex instance to another multiplex instance all substream data will be multiplexed and demultiplexed on the other end.

onStream will be called with (stream, id) whenever a new remote sub-stream is created with an id that hasn't already been created with .createStream.

Options include:

  • opts.limit - set the max allowed message size. default is no maximum

Any other options set in options are used as defaults options when creating sub streams.

stream = multiplex.createStream([id], [options])

Creates a new sub-stream with an optional whole string id (default is the stream channel id).

Sub-streams are duplex streams.

Options include:

  • opts.chunked - enables chunked mode on all streams (message framing not guaranteed)
  • opts.halfOpen - make channels support half open mode meaning that they can be readable but not writable and vice versa

stream = multiplex.receiveStream(id, [options])

Explicitly receive an incoming stream.

This is useful if you have a function that accepts an instance of multiplex and you want to receive a substream.

stream = multiplex.createSharedStream(id, [options])

Create a shared stream. If both ends create a shared stream with the same id, writing data on one end will emit the same data on the other end


multiplex.on('error', function (err) {})

Emitted when the outer stream encounters invalid data

multiplex.on('stream', function (stream, id) {})

Emitted when a it a new stream arrives.

stream.on('error', function (err) {})

Emitted if the inner stream is destroyed with an error


var multiplex = require('multiplex')
var plex1 = multiplex()
var stream1 = plex1.createStream()
var stream2 = plex1.createStream()

var plex2 = multiplex(function onStream(stream, id) {
  stream.on('data', function(c) {
    console.log('data', id, c.toString())


stream1.write(new Buffer('stream one!'))
stream2.write(new Buffer('stream two!'))


multiplex is an OPEN Open Source Project. This means that:

Individuals making significant and valuable contributions are given commit-access to the project to contribute as they see fit. This project is more like an open wiki than a standard guarded open source project.

See the CONTRIBUTING.md file for more details.


multiplex is only possible due to the excellent work of the following contributors: