1 | # isStream
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2 |
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3 | [![Build Status](https://secure.travis-ci.org/rvagg/isstream.png)](http://travis-ci.org/rvagg/isstream)
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4 |
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5 | **Test if an object is a `Stream`**
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6 |
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7 | [![NPM](https://nodei.co/npm/isstream.svg)](https://nodei.co/npm/isstream/)
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8 |
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9 | 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](https://github.com/isaacs/readable-stream)**.
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10 |
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11 | ## Usage:
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12 |
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13 | ```js
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14 | var isStream = require('isstream')
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15 | var Stream = require('stream')
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16 |
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17 | isStream(new Stream()) // true
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18 |
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19 | isStream({}) // false
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20 |
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21 | isStream(new Stream.Readable()) // true
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22 | isStream(new Stream.Writable()) // true
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23 | isStream(new Stream.Duplex()) // true
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24 | isStream(new Stream.Transform()) // true
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25 | isStream(new Stream.PassThrough()) // true
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26 | ```
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27 |
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28 | ## But wait! There's more!
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29 |
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30 | You can also test for `isReadable(obj)`, `isWritable(obj)` and `isDuplex(obj)` to test for implementations of Streams2 (and Streams3) base classes.
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31 |
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32 | ```js
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33 | var isReadable = require('isstream').isReadable
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34 | var isWritable = require('isstream').isWritable
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35 | var isDuplex = require('isstream').isDuplex
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36 | var Stream = require('stream')
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37 |
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38 | isReadable(new Stream()) // false
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39 | isWritable(new Stream()) // false
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40 | isDuplex(new Stream()) // false
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41 |
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42 | isReadable(new Stream.Readable()) // true
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43 | isReadable(new Stream.Writable()) // false
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44 | isReadable(new Stream.Duplex()) // true
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45 | isReadable(new Stream.Transform()) // true
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46 | isReadable(new Stream.PassThrough()) // true
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47 |
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48 | isWritable(new Stream.Readable()) // false
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49 | isWritable(new Stream.Writable()) // true
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50 | isWritable(new Stream.Duplex()) // true
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51 | isWritable(new Stream.Transform()) // true
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52 | isWritable(new Stream.PassThrough()) // true
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53 |
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54 | isDuplex(new Stream.Readable()) // false
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55 | isDuplex(new Stream.Writable()) // false
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56 | isDuplex(new Stream.Duplex()) // true
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57 | isDuplex(new Stream.Transform()) // true
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58 | isDuplex(new Stream.PassThrough()) // true
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59 | ```
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60 |
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61 | *Reminder: when implementing your own streams, please [use **readable-stream** rather than core streams](http://r.va.gg/2014/06/why-i-dont-use-nodes-core-stream-module.html).*
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62 |
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63 |
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64 | ## License
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65 |
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66 | **isStream** is Copyright (c) 2015 Rod Vagg [@rvagg](https://twitter.com/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.
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