stream-worker

stream-worker 
=============

Execute an async function per stream data event, pausing the stream when a concurrency limit is saturated. Inspired by async.queue, optimized for streams.

Supports promises and callbacks.

The Basics
----------

``
npm install stream-worker
`

Requiring:

`js
var streamWorker = require('stream-worker');
`


Promise style:
`js
function doWork(data){
/ ... do some work with data ... /
return Promise.resolve();
}
streamWorker(stream, doWork, {promises : true, concurrency : 10})
.then(function() {
/ ... the stream is exhausted and all workers are finished ... /
}, function(err) {
/ ... there was an error processing the stream ... /
})
`


Callback style:

`js

function doWork(data, done){
/ ... do some work with data ... /
return done(err);;
}
streamWorker(stream, doWork, {promises : false, concurrency :10},
function(err) {
/ ... the stream is exhauseted and all workers are finished ... /
}
);
``

Signature
---------
streamWorker(stream, work, options, done)

Where options is an object with 2 optional parameters:

| Parameter | Default | Description|
|------------- |-------------| -----|
| promises |false| true if you want to use the above promises style|
| concurrency| 10|specifies how many concurrent workers you want doing work in the stream |

And done is a callback function if you use the callback workflow.