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.
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
});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 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 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.
Neo-Async is compatible with Async.js, it is faster and has more feature.
Async is a utility module which provides staright-forward.
<script src="async.min.js"></script>
require(['async.min'], function(async) {});
$ npm install neo-async
var async = require('neo-async');
$ npm install neo-async
$ ln -s ./node_modules/neo-async ./node_modules/async
var async = require('async');
concatconcatSeriesconcatLimitdetectdetectSeriesdetectLimiteacheachSerieseachLimiteveryeverySerieseveryLimitfilterfilterSeriesfilterLimitforEachforEachSeriesforEachLimitmapmapSeriesmapLimitmultiEachpickpickSeriespickLimitreducereduceRightrejectrejectSeriesrejectLimitselectselectSeriesselectLimitsomesomeSeriessomeLimitsortBysortBySeriessortByLimittransformtransformSeriestransformLimitArguments
var order = [];
var collection = [1, 3, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(null, num);
}, num * 10);
};
async.concat(collection, iterator, function(err, array) {
assert.deepEqual(array, [1, 2, 3]);
assert.deepEqual(order, [1, 2, 3]);
});
Arguments
var order = [];
var collection = [1, 3, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(null, num);
}, num * 10);
};
async.concatSeries(collection, iterator, function(err, array) {
assert.deepEqual(array, [1, 3, 2]);
assert.deepEqual(order, [1, 3, 2]);
});
Arguments
var order = [];
var collection = [1, 3, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(null, num);
}, num * 10);
};
async.concatLimit(collection, 2, iterator, function(err, array) {
assert.deepEqual(array, [1, 3, 2]);
assert.deepEqual(order, [1, 3, 2]);
});
Arguments
var order = [];
var collection = [1, 3, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num === 3);
}, num * 10);
};
async.detect(collection, iterator, function(item) {
assert.deepEqual(item, 3);
assert.deepEqual(order, [1, 2, 3]);
});
Arguments
var order = [];
var collection = [1, 3, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num === 3);
}, num * 10);
};
async.detectSeries(collection, iterator, function(item) {
assert.deepEqual(item, 3);
assert.deepEqual(order, [1, 3]);
});
Arguments
var order = [];
var collection = [1, 3, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num === 3);
}, num * 10);
};
async.detectLimit(collection, 2, iterator, function(item) {
assert.deepEqual(item, 3);
assert.deepEqual(order, [1, 3]);
});
Aliases
async.forEach
Arguments
var order = [];
var collection = [1, 3, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done();
}, num * 10);
};
async.each(collection, iterator, function(err) {
assert.deepEqual(order, [1, 2, 3]);
});
Aliases
async.forEachSeries
Arguments
var order = [];
var collection = [1, 3, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done();
}, num * 10);
};
async.eachSeries(collection, iterator, function(err) {
assert.deepEqual(order, [1, 3, 2]);
});
Aliases
async.forEachLimit
Arguments
var order = [];
var collection = [1, 3, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done();
}, num * 10);
};
async.eachLimit(collection, 2, iterator, function(err) {
assert.deepEqual(order, [1, 3, 2]);
});
Arguments
var order = [];
var collection = [1, 3, 2, 4];
var iterator = function(num, callback) {
setTimeout(function() {
order.push(num);
callback(num % 2);
}, num * 10);
};
async.every(collection, iterator, function(bool) {
assert.strictEqual(bool, false);
assert.deepEqual(order, [1, 2]);
done();
});
Arguments
var order = [];
var collection = [1, 3, 2, 4];
var iterator = function(num, callback) {
setTimeout(function() {
order.push(num);
callback(num % 2);
}, num * 10);
};
async.everySeries(collection, iterator, function(bool) {
assert.strictEqual(bool, false);
assert.deepEqual(order, [1, 3, 2]);
done();
});
Arguments
var limit = 2;
var order = [];
var collection = [1, 3, 2, 4];
var iterator = function(num, callback) {
setTimeout(function() {
order.push(num);
callback(num % 2);
}, num * 10);
};
async.everyLimit(collection, limit, iterator, function(bool) {
assert.strictEqual(bool, false);
assert.deepEqual(order, [1, 3, 2]);
done();
});
Arguments
var order = [];
var collection = [3, 1, 2, 4];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num % 2);
}, num * 10);
};
async.filter(collection, iterator, function(array) {
assert.deepEqual(array, [3, 1]);
assert.deepEqual(order, [1, 2, 3, 4]);
});
Arguments
var order = [];
var collection = [3, 1, 2, 4];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num % 2);
}, num * 10);
};
async.filterSeries(collection, iterator, function(array) {
assert.deepEqual(array, [3, 1]);
assert.deepEqual(order, [3, 1, 2, 4]);
});
Arguments
var order = [];
var collection = [3, 1, 2, 4];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num % 2);
}, num * 10);
};
async.filterLimit(collection, 2, iterator, function(array) {
assert.deepEqual(array, [3, 1]);
assert.deepEqual(order, [1, 3, 2, 4]);
});
Arguments
var order = [];
var collection = [1, 3, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(null, num);
}, num * 10);
};
async.map(collection, iterator, function(err, array) {
assert.deepEqual(array, [1, 3, 2]);
assert.deepEqual(order, [1, 2, 3]);
});
Arguments
var order = [];
var collection = [1, 3, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(null, num);
}, num * 10);
};
async.mapSeries(collection, iterator, function(err, array) {
assert.deepEqual(array, [1, 3, 2]);
assert.deepEqual(order, [1, 3, 2]);
});
Arguments
var order = [];
var collection = [1, 3, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(null, num);
}, num * 10);
};
async.mapLimit(collection, 2, iterator, function(err, array) {
assert.deepEqual(array, [1, 3, 2]);
assert.deepEqual(order, [1, 3, 2]);
});
Arguments
synchronous
vvar order = [];
var array = [1, 2, 3];
var tasks = [
function(num, index, callback) {
order.push(num);
callback(null, array);
},
function(num, index, callback) {
order.push(num);
callback(null, array);
},
function(num, index, callback) {
order.push(num);
callback(null, array);
},
function(num, index, callback) {
order.push(num);
callback();
}
];
// get same result
var _order = [];
array.forEach(function(num) {
_order.push(num);
array.forEach(function(num) {
_order.push(num);
array.forEach(function(num) {
_order.push(num);
array.forEach(function(num) {
_order.push(num);
});
});
});
});
async.multiEach(array, tasks, function(err) {
assert.deepEqual(order, _order);
});
asynchronous
var order = [];
var array = [1, 2, 3];
var collection = {
a: [array, array],
b: {
c: array,
d: array
}
};
var delay = [25, 10];
var tasks = [
function(collection, key, callback) {
setTimeout(function() {
callback(null, array);
}, delay.shift());
},
function(collection, key, callback) {
callback(null, array);
},
function(value, key, callback) {
setTimeout(function() {
order.push(value);
callback();
}, value * 10);
}
];
async.multiEach(collection, tasks, function(err) {
assert.deepEqual(order, [
1, 1, 1,
2, 2, 2,
1, 1, 1,
3, 3, 3,
2, 2, 2,
3, 3, 3
]);
});
Arguments
var order = [];
var collection = [1, 3, 2, 4];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num % 2);
}, num * 10);
};
async.pick(collection, iterator, function(collection) {
assert.deepEqual(collection, [1, 3]);
assert.deepEqual(order, [1, 2, 3, 4]);
});
Arguments
var order = [];
var collection = [1, 3, 2, 4];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num % 2);
}, num * 10);
};
async.pickSeries(collection, iterator, function(collection) {
assert.deepEqual(collection, [1, 3]);
assert.deepEqual(order, [1, 3, 2, 4]);
});
Arguments
var order = [];
var collection = [1, 3, 2, 4];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num % 2);
}, num * 10);
};
async.pickLimit(collection, 2, iterator, function(collection) {
assert.deepEqual(collection, [1, 3]);
assert.deepEqual(order, [1, 3, 2, 4]);
});
Arguments
var order = [];
var collection = [1, 3, 2, 4];
var iterator = function(memo, num, done) {
setTimeout(function() {
order.push(num);
done(null, memo + num);
}, num * 10);
};
async.reduce(collection, 0, iterator, function(err, result) {
assert.strictEqual(result, 10);
assert.deepEqual(order, [1, 3, 2, 4]);
});
Arguments
var order = [];
var collection = [1, 3, 2, 4];
var iterator = function(memo, num, done) {
setTimeout(function() {
order.push(num);
done(null, memo + num);
}, num * 10);
};
async.reduceRight(collection, 0, iterator, function(err, result) {
assert.strictEqual(result, 10);
assert.deepEqual(order, [4, 2, 3, 1]);
});
Arguments
var order = [];
var collection = [1, 3, 2, 4];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num % 2);
}, num * 10);
};
async.reject(collection, iterator, function(collection) {
assert.deepEqual(collection, [2, 4]);
assert.deepEqual(order, [1, 2, 3, 4]);
});
Arguments
var order = [];
var collection = [1, 3, 2, 4];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num % 2);
}, num * 10);
};
async.rejectSeries(collection, iterator, function(collection) {
assert.deepEqual(collection, [2, 4]);
assert.deepEqual(order, [1, 3, 2, 4]);
});
Arguments
var order = [];
var collection = [1, 3, 2, 4];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num % 2);
}, num * 10);
};
async.rejectLimit(collection, 2, iterator, function(collection) {
assert.deepEqual(collection, [2, 4]);
assert.deepEqual(order, [1, 3, 2, 4]);
});
Arguments
var order = [];
var collection = [3, 1, 2, 4];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num % 2);
}, num * 10);
};
async.some(collection, iterator, function(bool) {
assert.ok(bool);
assert.deepEqual(order, [1]);
});
Arguments
var order = [];
var collection = [3, 1, 2, 4];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num % 2);
}, num * 10);
};
async.someSeries(collection, iterator, function(bool) {
assert.ok(bool);
assert.deepEqual(order, [3]);
});
Arguments
var order = [];
var collection = [3, 1, 2, 4];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(num % 2);
}, num * 10);
};
async.someLimit(collection, 2, iterator, function(bool) {
assert.ok(bool);
assert.deepEqual(order, [1]);
});
Arguments
var order = [];
var collection = [3, 1, 4, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(null, num % 2);
}, num * 10);
};
async.sortBy(collection, iterator, function(err, array) {
assert.deepEqual(array, [4, 2, 3, 1]);
assert.deepEqual(order, [1, 2, 3, 4]);
});
Arguments
var order = [];
var collection = [3, 1, 4, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(null, num % 2);
}, num * 10);
};
async.sortBySeries(collection, iterator, function(err, array) {
assert.deepEqual(array, [4, 2, 3, 1]);
assert.deepEqual(order, [3, 1, 4, 2]);
});
Arguments
var order = [];
var collection = [3, 1, 4, 2];
var iterator = function(num, done) {
setTimeout(function() {
order.push(num);
done(null, num % 2);
}, num * 10);
};
async.sortByLimit(collection, 2, iterator, function(err, array) {
assert.deepEqual(array, [4, 2, 3, 1]);
assert.deepEqual(order, [1, 3, 2, 4]);
});
Arguments
var order = [];
var collection = [1, 5, 3, 2, 4];
var iterator = function(memo, num, index, done) {
setTimeout(function() {
order.push(num);
if (num % 2) {
memo.push(num);
}
done();
}, num * 10);
};
async.transform(collection, iterator, function(err, result) {
assert.deepEqual(result, [1, 3, 5]);
assert.deepEqual(order, [1, 2, 3, 4, 5]);
});
Arguments
var order = [];
var collection = [1, 5, 3, 2, 4];
var iterator = function(memo, num, index, done) {
setTimeout(function() {
order.push(num);
if (num % 2) {
memo.push(num);
}
done();
}, num * 10);
};
async.transformSeries(collection, iterator, function(err, result) {
assert.deepEqual(result, [1, 5, 3]);
assert.deepEqual(order, [1, 5, 3, 2, 4]);
});
Arguments
var order = [];
var collection = [1, 5, 3, 2, 4];
var iterator = function(memo, num, index, done) {
setTimeout(function() {
order.push(num);
if (num % 2) {
memo.push(num);
}
done();
}, num * 10);
};
async.transformLimit(collection, 2, iterator, function(err, result) {
assert.deepEqual(result, [1, 5, 3]);
assert.deepEqual(order, [1, 5, 2, 3, 4]);
});
'use strict';
var comparator = require('func-comparator');
var _ = require('lodash');
var async = require('async');
var neo_async = require('neo-async');
// roop count
var count = 10;
// sampling times
var times = 1000;
var array = _.shuffle(_.times(count));
var tasks = _.map(array, function(n, i) {
if (i === 0) {
return function(next) {
next(null, n);
};
}
return function(total, next) {
next(null, total + n);
};
});
var funcs = {
'async': function(callback) {
async.waterfall(tasks, callback);
},
'neo-async': function(callback) {
neo_async.waterfall(tasks, callback);
}
};
comparator
.set(funcs)
.option({
async: true,
times: times
})
.start()
.result(function(err, res) {
console.log(res);
});
execute
# using garbage collection per execute
$ node --exsepo_gc speed_test/controlFlow/sample.waterfall.js
result
{ async:
{ min: 91.79,
max: 1751.06,
average: 275.01,
variance: 55185.67,
standard_deviation: 234.91,
vs: { 'neo-async': 41 } }, //[%] 100 * neo_async.average / async.average
'neo-async':
{ min: 16.55,
max: 600.16,
average: 112.78,
variance: 11310.35,
standard_deviation: 106.35,
vs: { async: 243.84 } } }
Collections
| function | count | times | async/neo-async |
|---|---|---|---|
| concat | 10 | 1000 | 125.77 |
| concatSeries | 10 | 1000 | 101.81 |
| detect | 10 | 1000 | 282.77 |
| detectSeries | 10 | 1000 | 112.06 |
| each | 10 | 1000 | 111.66 |
| eachSeries | 10 | 1000 | 94.08 |
| eachLimit | 10 | 1000 | 154.82 |
| every | 10 | 1000 | 217.7 |
| filter | 10 | 1000 | 279.27 |
| filterSeries | 10 | 1000 | 242.97 |
| map | 10 | 1000 | 473.08 |
| mapSeries | 10 | 1000 | 359.44 |
| mapLimit | 10 | 1000 | 590.42 |
| reduce | 10 | 1000 | 102.36 |
| reduceRight | 10 | 1000 | 341.52 |
| some | 10 | 1000 | 266.78 |
| sortBy | 10 | 1000 | 135.18 |
ControlFlow
| function | count | times | async/neo-async |
|---|---|---|---|
| waterfall | 10 | 1000 | 243.84 |
| waterfall | 50 | 1000 | 413.35 |
| parallel | 10 | 1000 | 145.45 |
| parallelLimit | 10 | 1000 | 196.36 |
| series | 10 | 500 | 140.98 |
FAQs
Neo-Async is a drop-in replacement for Async, it almost fully covers its functionality and runs faster
The npm package neo-async receives a total of 18,851,847 weekly downloads. As such, neo-async popularity was classified as popular.
We found that neo-async demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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