ios-dependency-injection

name	ios-dependency-injection
description	Standards for Protocol-based DI, Property Wrappers, and Factory/Needle. Use when configuring dependency injection or factory patterns in iOS. (triggers: **/*.swift, @Injected, Resolver, Container, Swinject, register, resolve)

iOS Dependency Injection Standards

Priority: P0

Implementation Guidelines

Protocol-Based DI (Manual)

• Initializer Injection: Preferred method. Pass dependencies through init.
• Abstractions: Inject protocols instead of concrete classes to facilitate testing (Mocks/Stubs).

Modern Property Wrappers (Factory/Resolver)

• Factory: Use the Factory library for lightweight, type-safe navigation-friendly DI.
• Swinject: Use for enterprise-grade container-based DI in large modular projects.
• Injected: Use @Injected property wrappers for cleaner syntax in ViewModels.

Scoping

• Singleton: Use for app-wide services (Auth, Network, Database).
• Unique/Transient: Default for ViewModels and temporary workers.
• Graph/Cached: Use for shared data within a specific feature flow (Coordinator scope).

Anti-Patterns

• No global singleton access everywhere: Inject service via initializer.
• No Resolver.resolve() inside logic: Pass dependency via constructor.
• No direct class instantiation: Depend on protocols for testability.

References

• Manual & Library DI Setup