internal/promise

A lightweight implementation of CommonJS Promises/A for PHP

3.4.1 2025-10-24 08:50 UTC

Requires

• php: >=8.1.0

Requires (Dev)

• phpstan/phpstan: 1.12.28
• phpunit/phpunit: ^10.5
• rector/rector: ^1.2
• spiral/code-style: ^2.2
• ta-tikoma/phpunit-architecture-test: ^0.8.5

Replaces

• react/promise: ^3.0

MIT

• Jan Sorgalla
• Christian Lück
• Cees-Jan Kiewiet
• Chris Boden

• promises
• promise

README

A lightweight implementation of CommonJS Promises/A for PHP.

Note

This is a fork of reactphp/promise.

Improvements over original reactphp/promise:

• PHP 8.1+ compatibility
• declare(strict_types=1); in all PHP files
• @yield annotation in the PromiseInterface

Version 3.x specific:

• Replaces react/promise v3 in Composer
• Rejection handler is reusable now. error_log() is still used by default.
• Removed exit(255) from RejectionPromise.

Version 2.x specific:

• Replaces react/promise v2 in Composer
• Enhanced type annotations

Install

composer require internal/promise

Tests

To run the test suite, go to the project root and run:

composer test

On top of this, we use PHPStan on max level to ensure type safety across the project:

composer stan

Credits

This fork is based on reactphp/promise, which is a port of when.js by Brian Cavalier.

Also, large parts of the documentation have been ported from the when.js Wiki and the API docs.