more-streams

A collection of useful stream implementations.

This is a library that makes a number of general purpose stream implementation available for your everyday use. This collection will grow over time, so don't hesitate to make feature requests for a stream implementation that you think should be in this library.

Installation

npm install --save more-streams

Requirements

This library has been written to work with Node.js v6.x and the latest ES2015 features.

API

There are 2 ways to include streams:

var CountStream = require('more-streams').CountStream;

or

var CountStream = require('more-streams/CountStream');

All streams extend a standard stream implementation and pass on any constructor options that are standard for this type of stream. Some of the helpers extend that options object for their specific use.

For more details take a look at the jsdoc and the tests.

ConsoleStream

This is a stream that outputs data to console (or any other output). It supports coloring output based on regular expression matches.

var ConsoleStream = require('more-streams/ConsoleStream');
var out = new ConsoleStream({
  colors: [{
    match: /error/g,
    styles: ['red', 'bold']
  }]
});
otherStream.pipe(out);

// -> prints to console with errors in bold and red

For more styles that you can apply take a look at chalk

CountStream

This is a stream that will count the number of bytes that have passed through.

var CountStream = require('more-streams/CountStream');
var counter = new CountStream();
counter.on('end', () => console.log(counter.count)); // -> prints total stream bytes count
otherStream.pipe(counter).pipe(process.stdout);

The stream also allows you to set markers which will trigger an event that you can react to.

var CountStream = require('more-streams/CountStream');
var counter = new CountStream();
counter.addMarker(10);
counter.on('marker', (count, counter) => console.log(count, counter.count)); // -> prints 10, 10
otherStream.pipe(counter).pipe(process.stdout);

MultiplexStream

A stream that will copy data and pipe it to multiple streams.

var MultiplexStream = require('more-streams/MultiplexStream');
var mux = new MultiplexStream();
otherStream.pipe(mux).pipe([process.stdout, process.stdout]);

// -> prints same output to 2 consoles

OffsetStream

A stream that allows to omit data from the beginning and end of another stream.

var OffsetStream = require('more-streams/OffsetStream');
var offset = new OffsetStream({start: 10, end: 20});
otherStream.pipe(offset).pipe(process.stdout);

// -> prints from 10th byte to 20th byte of the total stream

SequenceStream

A stream that allows to sequentially read data from multiple streams into one.

var SequenceStream = require('more-streams/SequenceStream');
var demux = new SequenceStream();
demux.chain(otherStream1, otherStream2, otherStream3);
demux.pipe(process.stdout);

// -> prints in order from stream 1,2 and then 3 to console.

Sink

A stream that will consume all data given. Optionally this stream can buffer all incoming data for later use.

var Sink = require('more-streams/Sink');
var buffer = new Sink({ buffer: true });
buffer.on('end', () => console.log(buffer.message('hex')));  // -> prints to console
otherStream.pipe(buffer);

Writer

A stream that can be preloaded with data ready to be read when a stream triggers a read.

var Writer = require('more-streams/Writer');
var output = new Writer();
output.write('message');
output.pipe(process.stdout);

// -> prints to console 'message'

Tests

To run tests and generate a coverage report run:

npm test