migration-patterns
Migration guides for CoreData to SwiftData, UIKit to SwiftUI, ObservableObject to @Observable, XCTest to Swift Testing, Objective-C to Swift, and StoreKit 1 to StoreKit 2. Use when migrating between Apple framework generations.
npx skills add rshankras/claude-code-apple-skills --skill migration-patterns --agent claude-code
Same command for any agent — swap --agent for codex, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# Migration Patterns Comprehensive guides for migrating between Apple framework generations. Each guide covers the full before/after mapping, coexistence strategies, and common pitfalls. ## When This Skill Activates - User asks how to migrate from CoreData to SwiftData - User is moving UIKit code to SwiftUI (or embedding one in the other) - User needs to update from ObservableObject/Combine to @Observable/AsyncSequence - User is converting XCTest tests to Swift Testing - User asks about coexistence strategies (running old and new frameworks side by side) - User wants to know whether a migration is worth doing for their situation - User is migrating Objective-C code to Swift (bridging headers, incremental migration) - User is migrating from StoreKit 1 to StoreKit 2 (in-app purchases, subscriptions) - User encounters errors during a framework migration ## Decision Tree ``` What are you migrating? | +-- Data persistence layer | +-- CoreData --> SwiftData | | See coredata-to-swiftdata.md | | Min: iOS 17 / macOS 14 | | | +-- Still need CoreData features SwiftData lacks? | Stay on CoreData or use coexistence mode | +-- UI framework | +-- UIKit --> SwiftUI | | See uikit-to-swiftui.md | |
- When This Skill Activates
- Decision Tree
- Quick Reference
- Process
- 1. Assess the Migration
- 2. Load Relevant Reference File
- 3. Review the User's Code
- 4. Recommend a Migration Strategy
- General Migration Principles
- References
What does the migration-patterns skill do?
Migration guides for CoreData to SwiftData, UIKit to SwiftUI, ObservableObject to @Observable, XCTest to Swift Testing, Objective-C to Swift, and StoreKit 1 to StoreKit 2. Use when migrating between Apple framework generations.
How do I install it?
Run `npx skills add rshankras/claude-code-apple-skills --skill migration-patterns --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From rshankras/claude-code-apple-skills, a repository with 589 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.