Container

A Swift Package for a modern approach to Service Locator for Swift and SwiftUI.

About

Container is inspired by the excellent Factory library, but designed as a lightweight alternative. This library focuses on simplicity while providing essential dependency injection features with fluent API and automatic mock injection for previews and tests. Rob-Yoo gives me strong inspiration that how to manage singleton instance when reference count is 0. Thank you for your advice :)

Installation

Swift Package Manager

Add Container to your project using Swift Package Manager. In Xcode:

1. Go to File → Add Package Dependencies
2. Enter the repository URL: https://github.com/donggyushin/Container
3. Select the version you want to use

Or add it to your Package.swift:

dependencies: [
    .package(url: "https://github.com/donggyushin/Container", from: "1.3.4")
]

Usage

Basic Registration

Register your dependencies using the fluent Factory API:

import Container

protocol Repository {
    func fetchData() -> String
}

class RepositoryImpl: Repository {
    func fetchData() -> String { "Real data" }
}

class RepositoryMock: Repository {
    func fetchData() -> String { "Mock data" }
}

extension Container {
    var repository: Factory<Repository> {
        self {
            RepositoryImpl()
        }
        .shared  // Optional: Use shared scope (singleton-like)
        .onPreview {
            RepositoryMock()  // Automatically used in Xcode Previews and Tests
        }
    }
}

Dependency Injection in ViewModels

Use the @Injected property wrapper for clean dependency injection:

class ViewModel: ObservableObject {
    @Injected(\.repository) private var repository

    func loadData() {
        let data = repository.fetchData()
        // Use data...
    }
}

Alternative Access Methods

You can also access dependencies directly:

// Method 1: Function call syntax
let repo = Container.shared.repository()

// Method 2: Wrapped value property
let repo = Container.shared.repository.wrappedValue

Scopes

Container supports two scopes:

• .shared: Creates a singleton instance (default)
• .unique: Creates a new instance each time

extension Container {
    var uniqueService: Factory<SomeService> {
        self {
            SomeService()
        }
        .unique  // New instance every time
    }
}

Default Scope Configuration

Set a default scope for all factories:

// In your app initialization
Container.shared.defaultScope = .shared

Requirements

• iOS 13.0+
• macOS 10.15+
• watchOS 6.0+
• tvOS 13.0+
• Swift 5.9+

License

donggyushin