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Awesome Promises

A curated list of useful resources for JavaScript Promises

Inspired by the 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

For beginners

Deep Dive


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.

Implementations with extras

All of these provide more features than the language yet remain compatible. Node + Browsers for all.

  • bluebird - Fully featured, extremely performant. Long stack traces & generator/coroutine support.
  • creed - Hyper performant & full featured like Bluebird, but FP-oriented. Coroutines, generators, promises, ES2015 iterables, & fantasy-land spec.
  • rsvp.js - Lightweight with a few extras. Compatible down to IE6!
  • Q - One of the original implementations. Long stack traces and other goodies.
  • then/promise - Small with nodeify, denodify and done() additions.
  • when.js - Packed with control flow, functional, and utility methods.


  • native-or-bluebird - Helps transition to completely native.
  • pinkie-promise - Use native, or fall back to pinkie. Great for node library authors.
  • 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)

  • delay - Delay a promise a specified amount of time.
  • pify - Promisify ("denodify") a callback-style function.
  • loud-rejection - Make unhandled promise rejections fail loudly instead of the default silent fail.
  • hard-rejection - Make unhandled promise rejections fail hard right away instead of the default silent fail
  • p-queue - Promise queue with concurrency control
  • p-break - Break out of a promise chain
  • p-lazy - Create a lazy promise that defers execution until .then() or .catch() is called
  • p-defer - Create a deferred promise
  • p-if - Conditional promise chains
  • p-tap - Tap into a promise chain without affecting its value or state
  • p-map - Map over promises concurrently
  • p-all - Run promise-returning & async functions concurrently with optional limited concurrency
  • p-limit - Run multiple promise-returning & async functions with limited concurrency
  • p-times - Run promise-returning & async functions a specific number of times concurrently
  • p-catch-if - Conditional promise catch handler
  • p-time - Measure the time a promise takes to resolve
  • p-log - Log the value/error of a promise
  • p-filter - Filter promises concurrently
  • p-settle - Settle promises concurrently and get their fulfillment value or rejection reason
  • p-memoize - Memoize promise-returning & async functions
  • p-whilst - Calls a function repeatedly while a condition returns true and then resolves the promise
  • p-throttle - Throttle promise-returning & async functions
  • p-debounce - Debounce promise-returning & async functions
  • p-retry - Retry a promise-returning or async function
  • p-wait-for - Wait for a condition to be true
  • p-timeout - Timeout a promise after a specified amount of time
  • p-race - A better Promise.race()
  • p-try - Promise#try() ponyfill - Starts a promise chain
  • p-finally - Promise#finally() ponyfill - Invoked when the promise is settled regardless of outcome
  • p-any - Wait for any promise to be fulfilled
  • p-some - Wait for a specified number of promises to be fulfilled
  • p-pipe - Compose promise-returning & async functions into a reusable pipeline
  • p-each-series - Iterate over promises serially
  • p-map-series - Map over promises serially
  • p-reduce - Reduce a list of values using promises into a promise for a value
  • p-props - Like Promise.all() but for Map and Object


  • promise-method - Standalone bluebird.method. Turn a synchronously-returning method into a promise-returning one.
  • is-promise - Determine if something looks like a Promise.
  • sprom - Resolve when a stream ends. Optional buffering (be careful with this!)
  • task.js - Write async functions in a blocking style using promises and generators. Like bluebird.coroutine.
  • co - Like task.js and bluebird.coroutine, but supports thunks too.
  • lie-fs - Promise wrappers for Node's FS API.
  • promise-do-until - Calls a function repeatedly until a condition returns true and then resolves the promise.
  • promise-do-whilst - Calls a function repeatedly while a condition returns true and then resolves the promise.
  • promise-semaphore - Push a set of work to be done in a configurable serial fashion
  • promise-nodeify - Standalone nodeify method which calls a Node-style callback on resolution or rejection.


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