# facebookarchive/KVOController

Simple, modern, thread-safe key-value observing for iOS and OS X.

Repository: https://github.com/facebookarchive/KVOController
Canonical: https://ross.abutalabs.com/products/kvocontroller
Language: Objective-C
License: NOASSERTION
License Family: other
Archived: true
Last push: 2020-01-25T04:18:28+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 4573, "days_push": 2412, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: archived, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 7286, forks 915 (observed 2026-08-28T04:09:58.030672+00:00)

## What it is
A thread-safe Objective-C library that simplifies Cocoa's key-value observing (KVO) on iOS and OS X. It offers a modern API supporting block-based, action-based, or NSKeyValueObserving callbacks with automatic observer cleanup on deallocation.

## Use cases
- observe object property changes safely in iOS apps
- replace raw KVO with block-based callbacks
- avoid crashes from observer resurrection and unbalanced removals
- communicate between model and view layers in MVC
- use KVO from Swift with dynamic properties
- auto-remove observers on dealloc without manual cleanup

## When to choose
- you need thread-safe KVO in Objective-C or Swift on iOS/macOS
- you want implicit observer removal to prevent leaks and crashes
- you prefer block callbacks over manual observeValueForKeyPath boilerplate

## When to avoid
- you can use Swift's native Combine or async observation APIs instead
- you target platforms other than iOS/OS X
- you need actively maintained software - the repo is archived

## Facets
- artifact type: library
- maturity: maintenance
- function: developer-tools, concurrency, error-handling
- domain: apple-ecosystem, developer-tools, mobile-development, cross-platform
- platform: cpp
- tags: key-value-observing, objective-c, cocoa, thread-safe, reactive, mvc, cocoapods, facebook-archive, ios, macos, swift

## Member repositories
- facebookarchive/KVOController (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:58.030672+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:38:52.430333+00:00, confidence not recorded.
  - readme: https://github.com/facebookarchive/KVOController (fetched 2026-08-28T04:09:58.030672+00:00, sha 901941f59ade)
- Data as of 2026-08-30T08:39:29.467469+00:00.