Promise.all
Promise.all is a JavaScript static method that returns a promise fulfilled with an array of results when all input promises fulfill, or rejected if any input promise rejects.
Get Programming with JavaScript Next: New features of ECMAScript 2015, 2016, and beyond
A Promise class method that returns a promise fulfilled when all input promises fulfill, or rejected when any input promise rejects.
- How it is used
- Combines multiple asynchronous requests when a result depends on all of them.
- How deep it goes
- Defines the aggregate promise and demonstrates joining requests, without detailing implementation internals.
- Examples
- Uses author-and-article requests and a credit-check task combining Promise.all with Promise.race.
- What you can do after
- Apply Promise.all to wait for multiple requests before using their combined results.
Secrets of the JavaScript Ninja, Second Edition
A JavaScript Promise combinator that returns a promise fulfilled when all input promises fulfill, or rejected if any input promise rejects.
- How it is used
- Coordinates independent asynchronous tasks in parallel and gathers their results before continuing.
- How deep it goes
- Specifies array input, fulfillment when all promises succeed, ordered results, and rejection if any promise fails.
- Examples
- Uses parallel JSON requests for ninja, map, and plan data, then checks the gathered results.
- What you can do after
- Apply it via Promise.all to wait for multiple asynchronous results and handle their shared success or failure.
Read how Secrets of the JavaScript Ninja, Second Edition explains Promise.all →
Related concepts
- promiseuses · A JavaScript Promise is an object representing the eventual completion or failure of an asynchronous operation and its resulting value or reason.
- Promise.racecontrasts with · Promise.race is a JavaScript static method that returns a promise settled with the outcome of the first input promise or thenable to settle.
- concurrencyuses · Concurrency is the structuring or execution of multiple computational activities so their progress overlaps in time, whether or not they run simultaneously.
- fork-join modelequivalent to · The fork-join model is a parallel computation pattern that divides work into concurrent subtasks and combines their results.
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