multistream

A stream that emits multiple other streams one after another (streams3)

Simple, robust streams3 version of combined-stream. Allows you to combine multiple streams into a single stream. When the first stream ends, the next one starts, and so on, until all streams are consumed.

This module is used by WebTorrent, specifically create-torrent.

install

npm install multistream

usage

Use multistream like this:

1var MultiStream = require('multistream')
2var fs = require('fs')
3
4var streams = [
5  fs.createReadStream(__dirname + '/numbers/1.txt'),
6  fs.createReadStream(__dirname + '/numbers/2.txt'),
7  fs.createReadStream(__dirname + '/numbers/3.txt')
8]
9
10new MultiStream(streams).pipe(process.stdout) // => 123

You can also create an object-mode stream with MultiStream.obj(streams).

To lazily create the streams, wrap them in a function:

1var streams = [
2  fs.createReadStream(__dirname + '/numbers/1.txt'),
3  function () { // will be executed when the stream is active
4    return fs.createReadStream(__dirname + '/numbers/2.txt')
5  },
6  function () { // same
7    return fs.createReadStream(__dirname + '/numbers/3.txt')
8  }
9]
10
11new MultiStream(streams).pipe(process.stdout) // => 123

Alternatively, streams may be created by an asynchronous "factory" function:

1var count = 0
2function factory (cb) {
3  if (count > 3) return cb(null, null)
4  count++
5  setTimeout(function () {
6    cb(null, fs.createReadStream(__dirname + '/numbers/' + count + '.txt'))
7  }, 100)
8}
9
10new MultiStream(factory).pipe(process.stdout) // => 123

contributors

• Feross Aboukhadijeh
• Mathias Buus
• Yuri Astrakhan

license

MIT. Copyright (c) Feross Aboukhadijeh.