yaku

What is yaku?

Yaku is a lightweight and fast Promise library that is fully compatible with ES6 Promises. It aims to provide better performance and smaller size compared to native Promises and other Promise libraries.

What are yaku's main functionalities?

Basic Promise Usage

This demonstrates the basic usage of Yaku to create a new Promise and handle its resolution.

const Yaku = require('yaku');

const promise = new Yaku((resolve, reject) => {
  setTimeout(() => resolve('Hello, Yaku!'), 1000);
});

promise.then(value => console.log(value));

Chaining Promises

This demonstrates how to chain multiple `then` calls to handle the resolved value step by step.

const Yaku = require('yaku');

const promise = new Yaku((resolve, reject) => {
  setTimeout(() => resolve(1), 1000);
});

promise
  .then(value => value + 1)
  .then(value => value * 2)
  .then(value => console.log(value));

Error Handling

This demonstrates how to handle errors in Yaku Promises using the `catch` method.

const Yaku = require('yaku');

const promise = new Yaku((resolve, reject) => {
  setTimeout(() => reject(new Error('Something went wrong')), 1000);
});

promise
  .then(value => console.log(value))
  .catch(error => console.error(error.message));

Promise.all

This demonstrates how to use `Yaku.all` to wait for multiple Promises to resolve.

const Yaku = require('yaku');

const promise1 = Yaku.resolve(1);
const promise2 = Yaku.resolve(2);
const promise3 = Yaku.resolve(3);

Yaku.all([promise1, promise2, promise3])
  .then(values => console.log(values));

Other packages similar to yaku

bluebird

Bluebird is a fully featured Promise library with a focus on performance and additional features not found in native Promises. It offers more utility methods and better error handling compared to Yaku, but it is larger in size.

q

Q is another Promise library that provides a lot of additional functionality such as deferred objects and more advanced control flow. It is more feature-rich compared to Yaku but also comes with a larger footprint.

when

When is a lightweight Promise library that focuses on performance and small size, similar to Yaku. It provides a few more utilities for working with Promises but is generally comparable in terms of performance and size.

README

Overview

The src/yaku.coffee of Yaku is full compatible with V8's native Promise, but much faster.

If you want to learn how Promise works, read the minimum implementation docs/minPromiseA+.coffee. Without comments, it is only 80 lines of code. It only implements the constructor and then. It passed all the tests of promises-aplus-tests.

I am not a optimization freak, I try to keep the source code readable and maintainable.

Features

• The minified file is only 2.7KB (Bluebird / 73KB, ES6-promise / 18KB)
• 100% compliant with Promise/A+ specs
• Better performance than the native Promise
• Works on IE5+ and other major browsers
• Possibly unhandled rejection support

Quick Start

Node.js

npm install yaku

Then:

Promise = require 'yaku'

Browser

Download the yaku.js file from release page. It supports both AMD and CMD. Raw usage without AMD or CMD:

<script type="text/javascript" src ="yaku.js"></script>
<script>
    // Yaku will be assigned to `window.Yaku`.
    Promise = Yaku
</script>

Compare

These comparisons only reflect some limited truth, no one is better than than others on all aspects.

iojs v1.8.1
OS   darwin
Arch x64
CPU  Intel(R) Core(TM) i7-4850HQ CPU @ 2.30GHz

Name	Unit Test	1ms async task	sync task	Helpers	file size
Yaku	872/872	283ms	68ms	++	2.7KB
Bluebird	872/872	244ms	164ms	+++++++	73KB
ES6-promise	872/872	435ms	110ms	+	18KB
native	872/872	816ms	605ms	+	0KB
q	208/872	2637ms	2327ms	+++	24K

• Helpers: extra methods that help with your promise programming, such as async flow control helpers, debug helpers.
• 1ms async task: npm run no -- benchmark, the smaller the better.
• sync task: npm run no -- benchmark --sync, the smaller the better.

API

FAQ

• Long stack trace support?

  Latest Node.js and browsers are already support it. If you enabled it, Yaku will take advantage of it without much overhead. Such as this library longjohn for Node.js, or this article for Chrome.

Unit Test

This project use promises-aplus-tests to test the compliance of Promise/A+ specification. There are about 900 test cases.

Use npm run no -- test to run the unit test.

Benchmark

Use npm run no -- benchmark to run the benchmark.

Misc.

The name yaku comes from the word 約束(yakusoku) which means promise.