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mxcl/PromiseKit

PromiseKit is a Swift and Objective-C library that provides a modern, thread-safe promise implementation with support for Swift concurrency and Apple's Combine framework. It offers comprehensive utilities for asynchronous programming, including image caching, error handling, and automation examples. The system ensures robustness through extensive test coverage, including Promises/A+ compliance, cross-platform compatibility, and bridging between Swift and Objective-C.

62.9

Adequate · 3 August 2026

2.7k

lines of production code

Swift

primary language

1

bus factor · 182 authors in all

3

measurements over time

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How it got here

2014–2015 · SwiftPM and modernization

This period focused on modernizing the build infrastructure and tooling, primarily through the adoption of Swift Package Manager and updates to CI and Xcode configurations. The codebase was also updated to support newer Swift versions and introduced features like async/await and Combine integration.

6 changes

2016 · Test coverage and playground fixes

This period focused on improving test coverage by adding comprehensive Promises-A+ compliance tests and bridging tests for AnyPromise. Additionally, the PromiseKit playground was repaired to resolve build issues, and all extension submodules were updated to their latest versions.

4 changes

2017–2024 · test coverage and compliance

This period focused on expanding test coverage across all major components, including the core promise types, Objective-C interoperability, and JavaScriptCore integration. The team also added a Promises/A+ compliance test suite and implemented a privacy manifest to ensure App Store compliance.

6 changes

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About this page

  • The description of this project is derived from its own commit history, not from its README.
  • The score is its highest published measurement, taken on 3 August 2026 at a pinned commit. It is not a live figure and does not change until the project is measured again.
  • Measured at commit 96cd3bdedf — the exact code this score is about.
  • Scored under rubric rubric-2026.08.18. Score the same commit under that rubric and you get the same number.
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