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

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

Speed Comparison

• async v0.9.0
• neo-async v0.4.9

Front-end

Speed comparison of front-end measured by jsPerf.
Measurement environment are as follows.

• Chrome 40.0.2214
• FireFox 34.0
• Safari 8.0.2

figure 1: waterfall sample

The value is the ratio (Neo-Async/Async) of the executions numbers per second.

function	Chrome	FireFox	Safari	url
waterfall	2.18	2.20	2.36	http://jsperf.com/async-waterfall/7
series	1.50	1.31	1.10	http://jsperf.com/async-series/8
parallel	15.67	10.17	5.01	http://jsperf.com/async-parallel/5
parallelLimit	1.35	1.41	1.11	http://jsperf.com/async-parallel-limit/2

Server-side

Speed comparison of server-side measured by func-comparator.
Specifications are as follows.

• n times trials
• Random execution order
• Execute GC every time
• Measure the average speed[μs] of n times

demo.js

var comparator = require('func-comparator');
var _ = require('lodash');
var async = require('async');
var neo_async = require('neo-async');

var count = 10; // the number of parallel tasks
var n = 1000; // the number of trial times
var array = _.shuffle(_.times(count));
var tasks = _.map(array, function(n) {
    return function(next) {
        next(null, n);
    };
});

// functions will be executed by random order
var funcs = {
    'async': function(callback) {
        async.parallel(tasks, callback);
    },
    'neo-async': function(callback) {
        neo_async.parallel(tasks, callback);
    }
};

comparator
.set(funcs)
.option({
    async: true,
    times: n
})
.start()
.result(console.log);

execute

• 10 times trials
• 1000 tasks

Execution environment are as follows.

• node v0.10.35
• iojs v1.0.2

$ node --expose_gc demo.js
$ iojs --expose_gc demo.js

result

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

function	node	iojs
waterfall	3.47	12.05
series	1.98	6.38
parallel	2.94	8.94
paralellLimit	2.88	6.13

The results show that we could improve perfomance by using either node or iojs.

Improvement of convenience

neo-async also have loop support for Object which is unsupported in async.

var object = {
    HOGE: 'hoge',
    FUGA: 'fuga',
    PIYO: 'piyo'
};

async.each(Object.keys(object), function(key, done) {
    var str = object[key];
    /* processing */
    done();
}, callback);

neo_async.each(object, function(str, done) {
    /* processing */
    done();
}, callback, thisArg);

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');

replacement

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

var async = require('async');

Bower

bower install neo-async

Feature not in Async

Collections

• concatLimit
• detectLimit
• everySeries
• everyLimit
• filterLimit
• pick
• pickSeries
• pickLimit
• rejectLimit
• selectLimit
• someSeries
• someLimit
• sortBySeries
• sortByLimit
• transform
• transformSeries
• transformLimit

Control Flow

• timesLimit

Utils

• eventEmitter