# Awesome Promises [](https://github.com/sindresorhus/awesome) > A curated list of useful resources for JavaScript Promises Inspired by the [awesome](https://github.com/sindresorhus/awesome) list thing. Not to be confused with other awesome promises like "I promise you a million dollars" or "I promise you'll stay fit and never have to go to the gym again". **Table of Contents** - [Resources, Blogs, and Books](#resources-blogs-and-books) - [Promises/A+ Implementations (ES6/ES2015 compatible)](#promisesa-implementations-es6es2015-compatible) - [Strict Implementations](#strict-implementations) - [Implementations with extras](#implementations-with-extras) - [Fallbacks](#fallbacks) - [Convenience Utilities](#convenience-utilities) ## Resources, Blogs, and Books ### For beginners * [Promise Cookbook](https://github.com/mattdesl/promise-cookbook) - The why, what, and how. "A brief introduction [...] primarily aimed at frontend developers". * [Promises for Asynchronous Programming](http://exploringjs.com/es6/ch_promises.html) - Chapter from [Exploring ES6](http://exploringjs.com/) * [You Don't Know JS: Promises](https://github.com/getify/You-Dont-Know-JS/blob/master/async%20&%20performance/ch3.md) - Chapter from [You Don't Know JS: Async & Performance](https://github.com/getify/You-Dont-Know-JS/tree/master/async%20%26%20performance) * [JavaScript Promises: an Introduction](https://developers.google.com/web/fundamentals/getting-started/primers/promises) - Basics of JavaScript's native promise implementation. * [JavaScript with Promises](http://shop.oreilly.com/product/0636920032151.do) - from O'Reilly. Short and to-the-point. Uses native and bluebird. * [Promise it won't hurt](https://github.com/stevekane/promise-it-wont-hurt) - An interactive [nodeschool](https://nodeschool.io/) workshop * [ES6 Kata Promises](http://es6katas.org/) - Promises Katas : [Basics](http://tddbin.com/#?kata=es6/language/promise/basics) * [ES6 Promises in Depth](https://ponyfoo.com/articles/es6-promises-in-depth) * [An Incremental Tutorial on Promises](http://www.sohamkamani.com/blog/2016/08/28/incremenal-tutorial-to-promises/) - An FAQ styled tutorial for beginners. ### Deep Dive * [Promise Fun](https://github.com/sindresorhus/promise-fun) - @sindresorhus's notes, patterns, and solutions to common Promise problems * [You're Missing the Point of Promises](https://blog.domenic.me/youre-missing-the-point-of-promises/) - Promises are much more than callback aggregation, and that jQuery's implementation (prior to 3.0) isn't enough. * [We have a problem with promises](https://pouchdb.com/2015/05/18/we-have-a-problem-with-promises.html) - "Many of us are using promises without really understanding them." * [Promise anti-patterns](https://github.com/petkaantonov/bluebird/wiki/Promise-anti-patterns) - Common misuses and how to avoid them. * [Promise anti-patterns (2)](http://taoofcode.net/promise-anti-patterns/) - Another set of promises anti-patterns * [Promise Ponderings, (Anti-)Patterns, and Apologies](https://sdgluck.github.io/2015/08/24/promise-ponderings-patterns-apologies/) - Promise behaviour demonstrated and explained by common questions and their answers. * [Javascript Promises...In Wicked Detail](http://www.mattgreer.org/articles/promises-in-wicked-detail/) - Recreate the promise implementation * [Writing Promise-Using Specifications](https://www.w3.org/2001/tag/doc/promises-guide) - "This document gives guidance on how to write specifications that create, accept, or manipulate promises" * [Async functions - making promises friendly](https://developers.google.com/web/fundamentals/getting-started/primers/async-functions) ### References * [Promises/A+ specification](https://promisesaplus.com/) * [caniuse promises](http://caniuse.com/#feat=promises) * [Fates and States](https://github.com/domenic/promises-unwrapping/blob/master/docs/states-and-fates.md) - Quick definitions of possible states. * [Promisees](https://bevacqua.github.io/promisees/) - Promise visualization playground for the adventurous. ## Promises/A+ Implementations (ES6/ES2015 compatible) ### Strict Implementations These implement no more or less than the es6 spec. They make great polyfills and are exceptionally compatible with native promises. * [pinkie](https://github.com/floatdrop/pinkie) - Ponyfill. Node-oriented, but [browserifyable](https://github.com/substack/node-browserify). *Extremely* small implementation. * [native-promise-only](https://github.com/getify/native-promise-only) - Polyfill. Browser and node-compatible. * [es6-promise](https://github.com/stefanpenner/es6-promise) - Opt-in polyfill. A strict-spec subset of rsvp.js. * [lie](https://github.com/calvinmetcalf/lie) - Small, browserifyable with an opt-in polyfill. ### Implementations with extras All of these provide more features than the language yet remain compatible. Node + Browsers for all. * [bluebird](https://github.com/petkaantonov/bluebird) - Fully featured, extremely performant. Long stack traces & generator/coroutine support. * [creed](https://github.com/briancavalier/creed) - Hyper performant & full featured like Bluebird, but FP-oriented. Coroutines, generators, promises, ES2015 iterables, & fantasy-land spec. * [rsvp.js](https://github.com/tildeio/rsvp.js/) - Lightweight with a few extras. Compatible down to IE6! * [Q](https://github.com/kriskowal/q) - One of the original implementations. Long stack traces and other goodies. * [then/promise](https://github.com/then/promise) - Small with `nodeify`, `denodify` and `done()` additions. * [when.js](https://github.com/cujojs/when) - Packed with control flow, functional, and utility methods. ### Fallbacks * [native-or-bluebird](https://www.npmjs.com/package/native-or-bluebird) - Helps transition to completely native. * [pinkie-promise](https://github.com/floatdrop/pinkie-promise) - Use native, or fall back to `pinkie`. Great for node library authors. * [any-promise](https://github.com/kevinbeaty/any-promise) - Loads the first available implementation. Safe for browserify. ## Convenience Utilities Native and strictly spec-compliant promises are awesome for compatibility, future-proofness, library authors, and browsers. However, libraries like bluebird patch goodies onto the `Promise` constructor and prototype. Solution? tiny modules of course! ### sindresorhus's many Promise utilities ([see notes](https://github.com/sindresorhus/promise-fun)) * [delay](https://github.com/sindresorhus/delay) - Delay a promise a specified amount of time. * [pify](https://github.com/sindresorhus/pify) - Promisify ("denodify") a callback-style function. * [loud-rejection](https://github.com/sindresorhus/loud-rejection) - Make unhandled promise rejections fail loudly instead of the default silent fail. * [hard-rejection](https://github.com/sindresorhus/hard-rejection) - Make unhandled promise rejections fail hard right away instead of the default silent fail * [p-queue](https://github.com/sindresorhus/p-queue) - Promise queue with concurrency control * [p-break](https://github.com/sindresorhus/p-break) - Break out of a promise chain * [p-lazy](https://github.com/sindresorhus/p-lazy) - Create a lazy promise that defers execution until `.then()` or `.catch()` is called * [p-defer](https://github.com/sindresorhus/p-defer) - Create a deferred promise * [p-if](https://github.com/sindresorhus/p-if) - Conditional promise chains * [p-tap](https://github.com/sindresorhus/p-tap) - Tap into a promise chain without affecting its value or state * [p-map](https://github.com/sindresorhus/p-map) - Map over promises concurrently * [p-all](https://github.com/sindresorhus/p-all) - Run promise-returning & async functions concurrently with optional limited concurrency * [p-limit](https://github.com/sindresorhus/p-limit) - Run multiple promise-returning & async functions with limited concurrency * [p-times](https://github.com/sindresorhus/p-times) - Run promise-returning & async functions a specific number of times concurrently * [p-catch-if](https://github.com/sindresorhus/p-catch-if) - Conditional promise catch handler * [p-time](https://github.com/sindresorhus/p-time) - Measure the time a promise takes to resolve * [p-log](https://github.com/sindresorhus/p-log) - Log the value/error of a promise * [p-filter](https://github.com/sindresorhus/p-filter) - Filter promises concurrently * [p-settle](https://github.com/sindresorhus/p-settle) - Settle promises concurrently and get their fulfillment value or rejection reason * [p-memoize](https://github.com/sindresorhus/p-memoize) - Memoize promise-returning & async functions * [p-whilst](https://github.com/sindresorhus/p-whilst) - Calls a function repeatedly while a condition returns true and then resolves the promise * [p-throttle](https://github.com/sindresorhus/p-throttle) - Throttle promise-returning & async functions * [p-debounce](https://github.com/sindresorhus/p-debounce) - Debounce promise-returning & async functions * [p-retry](https://github.com/sindresorhus/p-retry) - Retry a promise-returning or async function * [p-wait-for](https://github.com/sindresorhus/p-wait-for) - Wait for a condition to be true * [p-timeout](https://github.com/sindresorhus/p-timeout) - Timeout a promise after a specified amount of time * [p-race](https://github.com/sindresorhus/p-race) - A better `Promise.race()` * [p-try](https://github.com/sindresorhus/p-try) - `Promise#try()` ponyfill - Starts a promise chain * [p-finally](https://github.com/sindresorhus/p-finally) - `Promise#finally()` ponyfill - Invoked when the promise is settled regardless of outcome * [p-any](https://github.com/sindresorhus/p-any) - Wait for any promise to be fulfilled * [p-some](https://github.com/sindresorhus/p-some) - Wait for a specified number of promises to be fulfilled * [p-pipe](https://github.com/sindresorhus/p-pipe) - Compose promise-returning & async functions into a reusable pipeline * [p-each-series](https://github.com/sindresorhus/p-each-series) - Iterate over promises serially * [p-map-series](https://github.com/sindresorhus/p-map-series) - Map over promises serially * [p-reduce](https://github.com/sindresorhus/p-reduce) - Reduce a list of values using promises into a promise for a value * [p-props](https://github.com/sindresorhus/p-props) - Like `Promise.all()` but for `Map` and `Object` ### Others * [promise-method](https://github.com/wbinnssmith/promise-method) - Standalone `bluebird.method`. Turn a synchronously-returning method into a promise-returning one. * [is-promise](https://github.com/then/is-promise) - Determine if something looks like a Promise. * [sprom](https://github.com/then/sprom) - Resolve when a stream ends. Optional buffering (be careful with this!) * [task.js](https://github.com/mozilla/task.js) - Write async functions in a blocking style using promises and generators. Like `bluebird.coroutine`. * [co](https://github.com/tj/co) - Like `task.js` and `bluebird.coroutine`, but supports thunks too. * [lie-fs](https://www.npmjs.com/package/lie-fs) - Promise wrappers for Node's FS API. * [promise-do-until](https://github.com/busterc/promise-do-until) - Calls a function repeatedly until a condition returns true and then resolves the promise. * [promise-do-whilst](https://github.com/busterc/promise-do-whilst) - Calls a function repeatedly while a condition returns true and then resolves the promise. * [promise-semaphore](https://github.com/samccone/promise-semaphore) - Push a set of work to be done in a configurable serial fashion * [promise-nodeify](https://github.com/kevinoid/promise-nodeify) - Standalone `nodeify` method which calls a Node-style callback on resolution or rejection. ## License Licensed under the [Creative Commons CC0 License](https://creativecommons.org/publicdomain/zero/1.0/).