multi-stream.md

:MultiStream

An object consisting of multiple streams than can be refined or muxed.

The idea behind a MultiStream is being able to mux and demux streams when needed.

Usage:

new MultiStream([...streams])
 .mux();

new MultiStream(function*(){ yield* streams; })
 .map(stream => stream.filter(myFilter))
 .mux();

Kind: static class
Test: test/methods/multi-stream-constructor.js

• :MultiStream
  • new MultiStream(streams, [options])
  • multiStream.streams Array
  • multiStream.source DataStream
  • multiStream.length number
  • multiStream.map(aFunc, rFunc) ↺ Promise.<MultiStream>
  • multiStream.find() DataStream
  • multiStream.filter(func) ↺ MultiStream
  • multiStream.mux([comparator], [ClassType]) DataStream
  • multiStream.add(stream)
  • multiStream.remove(stream)
  • multiStream.route([policy], [count]) MultiStream
  • multiStream.smap(transform) ↺
  • multiStream.cluster(clusterFunc, [options]) ↺
  • MultiStream:from(streams, [StreamClass]) MultiStream

new MultiStream(streams, [options])

Crates an instance of MultiStream with the specified stream list

Param	Type	Default	Description
streams	Array.<stream.Readable> | AsyncGenerator.<Readable> | Generator.<Readable>		the list of readable streams (other objects will be filtered out!)
[options]	object	{}	Optional options for the super object. ;)

multiStream.streams : Array

Array of all streams

Kind: instance property of MultiStream

multiStream.source : DataStream

Source of the MultiStream.

This is nulled when the stream ends and is used to control the

Kind: instance property of MultiStream

multiStream.length : number

Returns the current stream length

Kind: instance property of MultiStream

multiStream.map(aFunc, rFunc) : Promise. ↺

Returns new MultiStream with the streams returned by the transform.

Runs a callback for every stream, returns a new MultiStream of mapped streams and creates a new MultiStream consisting of streams returned by the Function.

Kind: instance method of MultiStream
Chainable
Returns: Promise.<MultiStream> - the mapped instance
Test: test/methods/multi-stream-map.js

Param	Type	Description
aFunc	MultiMapCallback	Add callback (normally you need only this)
rFunc	MultiMapCallback	Remove callback, called when the stream is removed

multiStream.find() : DataStream

Calls Array.prototype.find on the streams

Kind: instance method of MultiStream
Returns: DataStream - found DataStream

Param	Type	Description
...args	Array.<any>	arguments for

multiStream.filter(func) : MultiStream ↺

Filters the stream list and returns a new MultiStream with only the streams for which the Function returned true

Kind: instance method of MultiStream
Chainable
Returns: MultiStream - the filtered instance
Test: test/methods/multi-stream-filter.js

Param	Type	Description
func	function	Filter ran in Promise::then (so you can return a promise or a boolean)

multiStream.mux([comparator], [ClassType]) : DataStream

Muxes the streams into a single one

Kind: instance method of MultiStream
Returns: DataStream - The resulting DataStream
Test: test/methods/multi-stream-mux.js
Todo

• For now using comparator will not affect the mergesort.
• Sorting requires all the streams to be constantly flowing, any single one drain results in draining the muxed too even if there were possible data on other streams.

Param	Type	Default	Description
[comparator]	function		Should return -1 0 or 1 depending on the desired order. If passed the chunks will be added in a sorted order.
[ClassType]	function	DataStream	the class to be outputted

multiStream.add(stream)

Adds a stream to the MultiStream

If the stream was muxed, filtered or mapped, this stream will undergo the same transforms and conditions as if it was added in constructor.

Kind: instance method of MultiStream
Meta.noreadme:
Test: test/methods/multi-stream-add.js

Param	Type	Description
stream	Readable	[description]

multiStream.remove(stream)

Removes a stream from the MultiStream

If the stream was muxed, filtered or mapped, it will be removed from same streams.

Kind: instance method of MultiStream
Meta.noreadme:
Test: test/methods/multi-stream-remove.js

Param	Type	Description
stream	Readable	[description]

multiStream.route([policy], [count]) : MultiStream

Re-routes streams to a new MultiStream of specified size

Kind: instance method of MultiStream
Returns: MultiStream - [description]
Meta.noreadme:
Todo

• NYT: not yet tested
• NYD: not yet documented

Param	Type	Default	Description
[policy]	function	Affinity.RoundRobin	[description]
[count]	number	os.cpus().length	[description]

multiStream.smap(transform) ↺

Map stream synchronously

Kind: instance method of MultiStream
Chainable

Param	Type	Description
transform	function	mapping function ran on every stream (SYNCHRONOUS!)

multiStream.cluster(clusterFunc, [options]) ↺

Distributes processing to multiple forked subprocesses.

Kind: instance method of MultiStream
Chainable

Param	Type	Default	Description
clusterFunc	function | string		a cluster callback with all operations working similarly to DataStream::use
[options]	DistributeOptions	{}

MultiStream:from(streams, [StreamClass]) : MultiStream

Constructs MultiStream from any number of streams-likes

Kind: static method of MultiStream

Param	Type	Default	Description
streams	Array.<(Array|Iterable.<any>|AsyncGeneratorFunction|GeneratorFunction|AsyncFunction|function()|string|Readable)>		the array of input streamlike elements
[StreamClass]	function	DataStream