flow-subtract

Transform stream factory to decrement streamed numeric data values.

Installation

$ npm install flow-subtract

API

To create a stream factory,

var subStream = require( 'flow-subtract' );
 
// Create a new factory:
var sStream = subStream();

sStream.subtract( [value] )

This method is a setter/getter. If no value is provided, returns the value subtracted from streamed values (a.k.a., the subtrahend); default is 0. To set the value,

sStream.subtract( 1 );

sStream.stream()

To create a new subtraction stream,

var stream = sStream.stream();

Usage

Methods are chainable.

subStream()
    .subtract( 1 )
    .stream()
    .pipe( /* writable stream */ );

Examples

var eventStream = require( 'event-stream' ),
    sStream = require( 'flow-subtract' );
 
// Create some data...
var data = new Array( 1000 );
for ( var i = 0; i < data.length; i++ ) {
    data[ i ] = Math.random();
}
 
// Create a readable stream:
var readStream = eventStream.readArray( data );
 
// Create a new subtraction stream:
var stream = sStream()
    .subtract( 1 )
    .stream();
 
// Pipe the data:
readStream.pipe( stream )
    .pipe( eventStream.map( function( d, clbk ) {
        clbk( null, d.toString()+'\n' );
    }))
    .pipe( process.stdout );

To run the example code from the top-level application directory,

$ node ./examples/index.js

Tests

Unit tests use the Mocha test framework with Chai assertions.

Assuming you have installed Mocha, execute the following command in the top-level application directory to run the tests:

$ mocha

All new feature development should have corresponding unit tests to validate correct functionality.

License

MIT license.

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Copyright

Copyright © 2014. Athan Reines.