Does it prevent the migration from running multiple times?

Yes, the generated methods include guards and state checks to ensure that migration logic is only executed once per data key.

What is the primary function of the SwiftData Migration Writer?

It generates standardized Swift code to safely migrate stored data from legacy UserDefaults storage into SwiftData entities.

Where should the migration logic be called?

The skill suggests adding the logic to a PreferencesStore extension and calling it during the app's first load or initialization phase.

How does it handle data integrity?

The skill implements validation checks, data preservation techniques, and archives old keys rather than deleting them immediately to ensure safe rollbacks if needed.

Can I use this for any iOS project?

Yes, while the underlying patterns were designed for the Leavn app, the migration logic and implementation patterns are standard for any iOS application using SwiftData.

SwiftData Migration Writer

Name: SwiftData Migration Writer
Author: willsigmon

bywillsigmon

•

Mobile Development

Generates robust migration logic to transition legacy UserDefaults storage into SwiftData entities with data validation and rollback support.

The SwiftData Migration Writer is designed to streamline the modernization of iOS application persistence layers by moving data from UserDefaults to Apple's modern SwiftData framework. It automates the mapping of legacy keys to entity fields, generates asynchronous migration methods, and implements critical safety features such as data preservation, key archiving, and state tracking to prevent duplicate migrations. This skill is essential for iOS developers who need to ensure a seamless transition for user preferences and settings while maintaining data integrity and providing a clear path for error handling.

主な機能

017 GitHub stars

02Automatic mapping of legacy UserDefaults keys to SwiftData entity properties

03Customizable validation logic to ensure data integrity during the transfer

04Data preservation strategies including legacy key archiving and rollback

05Asynchronous migration methods with built-in execution state tracking

06Seamless integration into PreferencesStore and app initialization workflows

ユースケース

01Upgrading an existing iOS app's data storage from UserDefaults to SwiftData

02Migrating user settings and preferences while ensuring no data loss

03Modernizing persistence architecture during major app refactors

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add willsigmon/sigstack swiftdata-migration-writer

For use in Claude.ai and ChatGPT

Download Skill