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:

1var isStream = require('isstream')
2var Stream = require('stream')
3
4isStream(new Stream()) // true
5
6isStream({}) // false
7
8isStream(new Stream.Readable())    // true
9isStream(new Stream.Writable())    // true
10isStream(new Stream.Duplex())      // true
11isStream(new Stream.Transform())   // true
12isStream(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.

1var isReadable = require('isstream').isReadable
2var isWritable = require('isstream').isWritable
3var isDuplex = require('isstream').isDuplex
4var Stream = require('stream')
5
6isReadable(new Stream()) // false
7isWritable(new Stream()) // false
8isDuplex(new Stream())   // false
9
10isReadable(new Stream.Readable())    // true
11isReadable(new Stream.Writable())    // false
12isReadable(new Stream.Duplex())      // true
13isReadable(new Stream.Transform())   // true
14isReadable(new Stream.PassThrough()) // true
15
16isWritable(new Stream.Readable())    // false
17isWritable(new Stream.Writable())    // true
18isWritable(new Stream.Duplex())      // true
19isWritable(new Stream.Transform())   // true
20isWritable(new Stream.PassThrough()) // true
21
22isDuplex(new Stream.Readable())    // false
23isDuplex(new Stream.Writable())    // false
24isDuplex(new Stream.Duplex())      // true
25isDuplex(new Stream.Transform())   // true
26isDuplex(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 licenced under the MIT licence. All rights not explicitly granted in the MIT license are reserved. See the included LICENSE.md file for more details.