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:

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

Promise style:

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:

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.