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https://github.com/airtoxin/dwarves
util streams
https://github.com/airtoxin/dwarves
Last synced: about 9 hours ago
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util streams
- Host: GitHub
- URL: https://github.com/airtoxin/dwarves
- Owner: airtoxin
- License: mit
- Created: 2014-11-08T04:37:03.000Z (almost 10 years ago)
- Default Branch: master
- Last Pushed: 2015-04-26T15:18:51.000Z (over 9 years ago)
- Last Synced: 2024-09-19T02:54:10.454Z (about 2 months ago)
- Language: JavaScript
- Size: 160 KB
- Stars: 0
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
dwarves
============
util streams for Node.js
Supports node v0.10
[](https://travis-ci.org/airtoxin/dwarves)
[](https://coveralls.io/r/airtoxin/dwarves?branch=master)
[](https://gemnasium.com/airtoxin/dwarves)
[](https://codeclimate.com/github/airtoxin/dwarves)
##Streams
###dwarves.toStream( array )
Creates readable data stream from array.
####Arguments
1. array(Array): The array to stream
####Example
```javascript
dwarves.toStream( [ 'a', 'b', 'c' ] )
.on( 'data', function ( d ) { console.log( d ); } );
// -> a
// -> b
// -> c
```
###dwarves.mapStream( mapper )
Creates transform stream which applies mapper function to data.
####Arguments
1. mapper(Function): The function called per streaming data to transform and emit processed data.
#####mapper( data, callback ) arguments
1. data(*): A streaming data.
2. callback(Function): The function called with emitting data to the next streams.
####Example
```javascript
var mapper = function ( data, callback ) {
callback( data * data );
};
dwarves.toStream( [ 1, 2, 3 ] )
.pipe( dwarves.mapStream( mapper ) )
.on( 'data', function ( d ) { console.log( d ); } );
// -> 1
// -> 4
// -> 9
```
###dwarves.reduceStream( initializer, reducer )
Creates transform stream which applies reducer function to aggregate if all data of previous stream have been gotten.
####Arguments
1. initializer(*): Initial value of accum.
2. reducer(Function): The function called to reduce data.
#####reducer( accum, data, callback ) arguments
1. accum(*): An accumlator used to memoize data.
2. data(*): A streaming data.
3. callback(Function): The function called with emitting data to the next streams.
####Example
```javascript
var reducer = function ( accum, data, callback ) {
callback( accum + data );
};
dwarves.toStream( [ 1, 2, 3, 4, 5 ] )
.pipe( dwarves.reduceStream( 0, reducer ) )
.on( 'data', function ( d ) { console.log( d ); } );
// -> 15
```
###dwarves.sampleStream( batchSize )
Creates transform stream which retrieves a random data from stream per batchSize.
####Arguments
1. batchSize(Integer): The number of data pool size.
####Example
```javascript
dwarves.toStream( [ 1, 2, 3, 4, 5 ] )
.pipe( dwarves.sampleStream( 3 ) )
.on( 'data', function ( d ) { console.log( d ); } );
// -> 3
// -> 4
```
###dwarves.shuffleStream( batchSize )
Creates transform stream which changes order of streaming data per batchSize.
####Arguments
1. batchSize(Integer): The number of data pool size.
####Example
```javascript
dwarves.toStream( [ 1, 2, 3, 4, 5 ] )
.pipe( dwarves.shuffleStream( 3 ) )
.on( 'data', function ( d ) { console.log( d ); } );
// -> 1
// -> 3
// -> 2
// -> 5
// -> 4
```
###dwarves.groupByStream( keyName, valueName, shuffler )
Creates transform object stream which composed of keys generated from the shuffler callback.
####Arguments
1. keyName(String): The key name of grouping key of transformed object stream.
2. valueName(String): The key name of grouped values of transformed object stream.
3. shuffler(Function): The function called to resolving grouping key name.
#####shuffler( data, callback ) arguments
1. data(*): A streaming data
2. callback(Function): The function called with key name of this data.
####Example
```javascript
var shuffler = function ( data, callback ) {
callback( data[ 0 ] );
};
dwarves.toStream( [ 'a', 'ab', 'bb', 'bc' ] )
.pipe( dwarves.groupByStream( 'k', 'v', shuffler ) )
.on( 'data', function ( d ) { console.log( d ); } );
// -> { k: 'a', v: [ 'a', 'ab' ] }
// -> { k: 'b', v: [ 'bb', 'bc' ] }
```