# IOS Dependency Injection

> Configure protocol-based DI with property wrappers and Factory/Swinject. Use when setting up dependency injection or factory patterns in iOS.

- Skill: `hoangnguyen0403/ios-dependency-injection` (Agent Skill, multi-file: 3 files)
- Install (CLI): `npx skillmds@latest add hoangnguyen0403/ios-dependency-injection`
- Raw SKILL.md: https://api.skillmd.com/api/skills/hoangnguyen0403/ios-dependency-injection/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: HoangNguyen0403 (https://skillmd.com/u/hoangnguyen0403)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/hoangnguyen0403/ios-dependency-injection

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# iOS Dependency Injection

## **Priority: P0 (CRITICAL)**

## Implementation Workflow

1. **Prefer initializer injection** — Pass dependencies through `init` as primary approach.
2. **Inject protocols** — Always depend on protocols instead of concrete classes for testability.
3. **Choose DI library** — Use `Factory` for lightweight DI, `Swinject` for enterprise-grade container-based projects.
4. **Apply correct scoping** — Singleton for app-wide services (Auth, Network); Unique/Transient for ViewModels; Graph/Cached for feature flows.

See [protocol-based DI and Factory registration examples](references/implementation.md)

## Anti-Patterns

- **No Global Singletons**: Inject services via initializer
- **No Inline Service Resolution**: Pass dependencies via constructor; avoid `Resolver.resolve()` in business logic
- **No Concrete Class Dependencies**: Depend on protocols for testability

## References

- [Manual & Library DI Setup](references/implementation.md)

## Canonical response anchors

When this skill applies, preserve the following domain terminology or equivalent concrete examples in the answer when relevant:
- Injected

## Remediation anchors

- Remediation anchors: protocol injection, Factory library, initializer injection