Does it handle data persistence during the transition?

The skill helps write the migration logic to ensure that existing user data is safely transferred from legacy keys to the new database entities upon the first launch.

What tools does this skill use to perform migrations?

It leverages Claude's built-in Read, Write, Edit, and Grep tools to search the repository, modify source code, and create new Swift files.

Can this skill create the new data models?

Yes, it can generate the necessary SwiftData entities and update your code to reference a centralized PreferencesStore instead of direct UserDefaults calls.

Does it migrate all UserDefaults automatically?

No, it follows a structured workflow to categorize data first. This ensures that items like debug flags or widget data stay in UserDefaults while core preferences move to SwiftData.

UserDefaults Migrator

Name: UserDefaults Migrator
Author: willsigmon

bywillsigmon

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Mobile Development

Automates the migration of legacy UserDefaults storage to modern SwiftData entities and PreferencesStore architectures.

The UserDefaults Migrator is a specialized tool designed to streamline the transition from legacy key-value storage to modern data persistence frameworks in Swift applications. It scans codebases for standard UserDefaults usage, intelligently categorizes items to determine if they should be migrated or retained, and automates the creation of SwiftData entities and migration logic. This skill is essential for iOS developers modernizing their app's architecture, ensuring a single source of truth for user settings and persistent data while cleaning up technical debt.

Key Features

01Safe archival workflows for deprecated storage keys

02Recursive codebase scanning for legacy UserDefaults.standard patterns

037 GitHub stars

04Automated SwiftData entity generation for migrated properties

05Intelligent categorization of settings vs. ephemeral debug flags

06Refactoring support for centralized PreferencesStore implementation

Use Cases

01Auditing and cleaning up technical debt associated with undocumented UserDefaults keys

02Modernizing legacy iOS app storage from plist-based storage to SwiftData

03Refactoring scattered settings management into a centralized PreferencesStore

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add willsigmon/sigstack userdefaults-migrator

For use in Claude.ai and ChatGPT

Download Skill