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55 lines
1.0 KiB
Markdown
55 lines
1.0 KiB
Markdown
# pull-stream/throughs/map
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> [].map for pull-streams
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## Background
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Pull-streams are arrays of data in time rather than space.
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As with a [`[].map`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map), we may want to map a function over a stream.
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## Example
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```js
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var map = require('pull-stream/throughs/map')
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```
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```js
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pull(
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values([0, 1, 2, 3]),
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map(function (x) {
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return x * x
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}),
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log()
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)
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// 0
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// 1
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// 4
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// 9
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```
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## Usage
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### `map = require('pull-stream/throughs/map')`
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### `map((data) => data)`
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`map(fn)` returns a through stream that calls the given `fn` for each chunk of incoming data and outputs the return value, in the same order as before.
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## Install
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With [npm](https://npmjs.org/) installed, run
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```
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$ npm install pull-stream
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```
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## See Also
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- [`brycebaril/through2-map`](https://github.com/brycebaril/through2-map)
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- [`Rx.Obsevable#map`](http://xgrommx.github.io/rx-book/content/observable/observable_instance_methods/map.html)
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## License
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[MIT](https://tldrlegal.com/license/mit-license)
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