rvagg/isstream

Determine if an object is a Node.js Stream

isStream

Test if an object is a Stream

The missing Stream.isStream(obj): determine if an object is standard Node.js Stream. Works for Node-core Stream objects (for 0.8, 0.10, 0.11, and in theory, older and newer versions) and all versions of readable-stream.

Usage:

var isStream = require('isstream')
var Stream = require('stream')

isStream(new Stream()) // true

isStream({}) // false

isStream(new Stream.Readable())    // true
isStream(new Stream.Writable())    // true
isStream(new Stream.Duplex())      // true
isStream(new Stream.Transform())   // true
isStream(new Stream.PassThrough()) // true

But wait! There's more!

You can also test for isReadable(obj), isWritable(obj) and isDuplex(obj) to test for implementations of Streams2 (and Streams3) base classes.

var isReadable = require('isstream').isReadable
var isWritable = require('isstream').isWritable
var isDuplex = require('isstream').isDuplex
var Stream = require('stream')

isReadable(new Stream()) // false
isWritable(new Stream()) // false
isDuplex(new Stream())   // false

isReadable(new Stream.Readable())    // true
isReadable(new Stream.Writable())    // false
isReadable(new Stream.Duplex())      // true
isReadable(new Stream.Transform())   // true
isReadable(new Stream.PassThrough()) // true

isWritable(new Stream.Readable())    // false
isWritable(new Stream.Writable())    // true
isWritable(new Stream.Duplex())      // true
isWritable(new Stream.Transform())   // true
isWritable(new Stream.PassThrough()) // true

isDuplex(new Stream.Readable())    // false
isDuplex(new Stream.Writable())    // false
isDuplex(new Stream.Duplex())      // true
isDuplex(new Stream.Transform())   // true
isDuplex(new Stream.PassThrough()) // true

Reminder: when implementing your own streams, please use readable-stream rather than core streams.

License

isStream is Copyright (c) 2015 Rod Vagg @rvagg and licensed under the MIT license. All rights not explicitly granted in the MIT license are reserved. See the included LICENSE.md file for more details.

isstream's Issues

Highlandjs

As highland is the main streaming Node.js framework, can you write in your docs, that isstream doesn't detect highland streams?

Doesn't actually work for Node-core Stream objects in 0.8

... because in Node 0.8 core streams, there are no _read or _write methods:

[~] nvm use 0.8
Now using node v0.8.28
[~] node
> require('isStream').isWritable(require('fs').createWriteStream('/tmp/foo'))
false
> require('isStream').isReadable(require('fs').createReadStream('/tmp/foo'))
false
> require('isStream').isDuplex(new (require('net').Socket)())
false
>
(^C again to quit)
>

[~] nvm use 0.10
Now using node v0.10.32
[~] node
> require('isStream').isWritable(require('fs').createWriteStream('/tmp/foo'))
true
> require('isStream').isReadable(require('fs').createReadStream('/tmp/foo'))
true
> require('isStream').isDuplex(new (require('net').Socket)())
true
>
(^C again to quit)
>

Broken link in README

The link in this line is broken:

Reminder: when implementing your own streams, please use readable-stream rather than core streams.

Drop tests from npm package

Hi,

Could you add:

test.js
.travis.yml

to .npmignore ?