neo-async

What is neo-async?

The neo-async package is a utility module which provides straight-forward, powerful functions for working with asynchronous JavaScript. It is similar to the async package but with some performance improvements.

What are neo-async's main functionalities?

Control Flow

Execute a series of functions in sequential order. Each function is passed a callback it must call on completion.

async.series([
  function(callback) {
    // do some stuff ...
    callback(null, 'one');
  },
  function(callback) {
    // do some more stuff ...
    callback(null, 'two');
  }
],
function(err, results) {
  // results is now equal to ['one', 'two']
});

Collections

Apply a function to each item in a collection and collect the results.

async.map(['file1','file2','file3'], fs.stat, function(err, results) {
  // results is now an array of stats for each file
});

Utilities

Call a function a certain number of times and collect the results.

async.times(5, function(n, next) {
  createUser(n, function(err, user) {
    next(err, user);
  });
}, function(err, users) {
  // we should now have 5 users
});

Other packages similar to neo-async

async

The original async package offers a wide array of functions for working with asynchronous code. Neo-async claims to offer similar functionality with improved performance.

bluebird

Bluebird is a full-featured promise library with a focus on innovative features and performance. It can be used as an alternative to neo-async for handling asynchronous operations using promises instead of callbacks.

q

Q is a tool for making and composing asynchronous promises in JavaScript. It's an older promise library that can serve similar purposes to neo-async but with a different style of handling async operations.

README

Neo-Async v1.8.2

Neo-Async is thought to be used as a drop-in replacement for Async, it almost fully covers its functionality and runs faster.

Async allows double callbacks in waterfall, but Neo-Async does not allow. (test) PR is welcome ! Especially improvement for English documents :)

Installation

In a browser

<script src="async.min.js"></script>

In an AMD loader

require(['async'], function(async) {});

Node.js

standard

$ npm install neo-async

var async = require('neo-async');

// safe mode
var async = require('neo-async').safe; // avoid stack overflow if iterator is called on sync.

replacement

$ npm install neo-async
$ ln -s ./node_modules/neo-async ./node_modules/async

var async = require('async');

Bower

bower install neo-async

Feature

JSDoc

* not in Async

Collections

• each
• eachSeries
• eachLimit
• forEach -> each
• forEachSeries -> eachSeries
• forEachLimit -> eachLimit
• eachOf -> each
• eachOfSeries -> eachSeries
• eachOfLimit -> eachLimit
• forEachOf -> each
• forEachOfSeries -> eachSeries
• eachOfLimit -> forEachLimit
• map
• mapSeries
• mapLimit
• mapValues *
• mapValuesSeries *
• mapValuesLimit *
• filter
• filterSeries
• filterLimit
• select -> filter
• selectSeries -> filterSeries
• selectLimit -> filterLimit
• reject
• rejectSeries
• rejectLimit
• detect
• detectSeries
• detectLimit
• pick *
• pickSeries *
• pickLimit *
• omit *
• omitSeries *
• omitLimit *
• reduce
• inject -> reduce
• foldl -> reduce
• reduceRight
• foldr -> reduceRight
• transform *
• transformSeries *
• transformLimit *
• sortBy
• sortBySeries
• sortByLimit *
• some
• someSeries
• someLimit
• any -> some
• every
• everySeries *
• everyLimit
• all -> every
• concat
• concatSeries
• concatLimit *

Control Flow

• parallel
• series
• parallelLimit
• waterfall
• angelFall *
• angelfall -> angelFall *
• whilst
• doWhilst
• until
• forever
• compose
• seq
• applyEach
• applyEachSeries
• queue
• priorityQueue
• cargo
• auto
• retry
• iterator
• timeout
• times
• timesSeries
• timesLimit

Utils

• apply
• nextTick
• setImmediate
• safeNextTick *
• asyncify
• wrapSync -> asyncify
• constant
• ensureAsync
• memoize
• unmemoize
• log
• dir
• createLogger
• noConflict
• eventEmitter *
• EventEmitter *
• safe *

Safe

var async = require('neo-async').safe;
// or
var async = require('neo-async');
async.safe.each(collection, iterator, callback);

Speed Comparison

• async v1.3.0
• neo-async v1.3.0

Server-side

Speed comparison of server-side measured by func-comparator.

Specifications are as follows.

• n times trials
• Random execution order
• Measure the average speed[μs] of n times

execute

• 100 times trials
• 500000 tasks

Execution environment are as follows.

• node v0.10.40
• node v0.12.7
• iojs v2.3.4

$ node perf/func-comparator

result

The value is the ratio (Neo-Async/Async) of the average speed per n times.

collections

function	node v0.10.40	node v0.12.7	iojs v2.3.4
each	2.01	1.95	2.19
eachSeries	2.28	2.62	2.28
eachLimit	2.33	3.32	2.81
eachOf	1.93	1.92	2.12
eachOfSeries	2.17	2.79	2.98
eachOfLimit	2.03	1.54	2.57
map	3.10	3.11	3.38
mapSeries	2.36	1.98	2.32
mapLimit	1.76	1.84	2.06
filter	2.33	3.70	6.59
filterSeries	2.11	2.71	3.68
reject	2.71	4.38	7.33
rejectSeries	2.31	3.09	3.86
detect	2.31	2.69	2.92
detectSeries	2.13	1.96	2.71
reduce	2.09	1.94	2.26
reduceRight	2.19	1.93	2.51
sortBy	1.41	1.66	1.52
some	2.23	2.29	2.50
every	2.22	2.25	2.93
concat	12.0	7.23	10.0
concatSeries	8.37	5.15	8.05

control flow

function	node v0.10.40	node v0.12.7	iojs v2.3.4
parallel	4.13	5.00	3.37
series	3.13	2.70	3.03
parallelLimit	2.69	2.96	2.49
waterfall	3.45	7.24	7.59
whilst	1.02	1.09	1.14
doWhilst	1.26	1.36	1.28
until	1.02	1.08	1.13
doUntil	1.25	1.31	1.34
during	2.15	2.08	2.08
doDuring	5.08	5.77	5.39
times	4.07	3.16	3.44
timesSeries	2.82	2.58	2.71
timesLimit	2.23	2.05	1.93