async vs bluebird | JavaScript Asynchronous Programming Comparison

Package	Downloads	Stars	Size	Issues	Publish	License

async	64,723,206	28,220	808 kB	18	a year ago	MIT
bluebird	30,848,023	20,588	-	123	6 years ago	MIT

Package

Downloads

Stars

Size

Issues

Publish

License

async

64,723,206

28,220

808 kB

a year ago

MIT

bluebird

30,848,023

20,588

123

6 years ago

MIT

Control Flow

async:
async provides functions for managing control flow in asynchronous operations, such as async.series, async.parallel, and async.waterfall. These functions allow you to execute tasks in a specific order or concurrently, making it easier to manage complex asynchronous workflows.
bluebird:
bluebird does not provide control flow functions like async, but it allows you to chain promises and use methods like Promise.all, Promise.race, and Promise.each to manage multiple asynchronous operations. It focuses on enhancing the promise-based approach rather than providing control flow utilities.

Promise Support

async:
async does not natively support promises, as it is designed to work with callbacks. However, it can be used alongside promises, and some of its functions can work with promise-returning functions if you handle the integration manually.
bluebird:
bluebird is a promise-centric library that fully embraces the promise paradigm. It provides a rich set of features for working with promises, including promise cancellation, progress reporting, and a variety of utility methods that enhance the standard promise API.

Performance

async:
async is lightweight and efficient for managing control flow, but its performance depends on how you use it. For example, using async.series can introduce delays if tasks are executed sequentially. However, it is generally performant for most use cases.
bluebird:
bluebird is known for its high performance, especially when handling large numbers of promises. It is optimized for speed and memory usage, making it one of the fastest promise implementations available. This makes it a great choice for performance-sensitive applications.

Error Handling

async:
async provides built-in error handling for asynchronous tasks. If an error occurs in a task, it can be propagated to the callback function, allowing you to handle it gracefully. However, error handling can become complex in nested or concurrent tasks.
bluebird:
bluebird offers advanced error handling capabilities, including the ability to catch errors at any point in the promise chain, handle multiple errors, and create custom error types. It provides a more robust and flexible approach to error handling compared to traditional promise implementations.

Example Code

async:

Example of async control flow

const async = require('async');

async.series([
  function(callback) {
    setTimeout(() => {
      console.log('Task 1');
      callback(null);
    }, 1000);
  },
  function(callback) {
    setTimeout(() => {
      console.log('Task 2');
      callback(null);
    }, 500);
  },
  function(callback) {
    setTimeout(() => {
      console.log('Task 3');
      callback(null);
    }, 300);
  }
], function(err) {
  if (err) console.error(err);
  console.log('All tasks completed.');
});

bluebird:

Example of bluebird promise

const Promise = require('bluebird');

const task1 = () => {
  return new Promise((resolve) => {
    setTimeout(() => {
      console.log('Task 1');
      resolve();
    }, 1000);
  });
};

const task2 = () => {
  return new Promise((resolve) => {
    setTimeout(() => {
      console.log('Task 2');
      resolve();
    }, 500);
  });
};

const task3 = () => {
  return new Promise((resolve) => {
    setTimeout(() => {
      console.log('Task 3');
      resolve();
    }, 300);
  });
};

Promise.all([task1(), task2(), task3()]).then(() => {
  console.log('All tasks completed.');
});

// for use with Node-style callbacks... var async = require("async"); var obj = {dev: "/dev.json", test: "/test.json", prod: "/prod.json"}; var configs = {}; async.forEachOf(obj, (value, key, callback) => { fs.readFile(__dirname + value, "utf8", (err, data) => { if (err) return callback(err); try { configs[key] = JSON.parse(data); } catch (e) { return callback(e); } callback(); }); }, err => { if (err) console.error(err.message); // configs is now a map of JSON data doSomethingWith(configs); });

var async = require("async"); // ...or ES2017 async functions async.mapLimit(urls, 5, async function(url) { const response = await fetch(url) return response.body }, (err, results) => { if (err) throw err // results is now an array of the response bodies console.log(results) })