leviathan-di

name	leviathan-di
description	Learn and apply Leviathan, a service-locator style DI library for Kotlin Multiplatform. Includes practical recipes for scopes, factories, mutable providers, Compose, ViewModel, testing, and modularization.
metadata	{"author":"ComposeGears","last-updated":"2026-05-21","keywords":["DI","service locator","recipe","Kotlin","Kotlin Multiplatform","Leviathan","Compose","ViewModel","testing","modularization"]}

Getting started

• Getting started: Install Leviathan and define your first dependencies.
• Core concepts: Understand DIScope, Dependency, MutableDependency, and lifecycle behavior.

Recipes

Base declarations

• Basic module: Declare singleton, instance, factory, and mutable dependencies.
• Constructor injection pattern: Keep constructors testable while resolving dependencies at boundaries.
• Top-level dependencies: Use app-wide dependencies and explicit scope control.

Lifetime and caching

• Scoped lifecycle: Model short-lived object graphs and release instances with scope closure.
• Factories and caching: Choose per-scope cached factories vs always-new instances.
• Singleton: holder-lifetime dependency: Keep an instance alive for the life of the declaring module, regardless of scope closures.

Dependency graphs

• Dependency graphs with inject: Build complex wired dependencies using inject(...) inside factory blocks.
• Interface binding: Bind implementations to interfaces for polymorphic injection.
• Circular dependencies: Resolve cycles by deferring injection with lambdas.

Runtime reconfiguration

• Mutable overrides: Swap implementations at runtime for flags, environments, and previews.
• Testing overrides: Override providers safely in tests and restore defaults.

Integrations

• Compose integration: Inject dependencies in Composables with inject and injectAndRetain.
• ViewModel integration: Scope dependencies to ViewModel lifecycle.

Architecture

• Feature modules: Organize declarations by feature without centralized containers.
• Global scope usage: Use DIScope.GLOBAL for app-wide singletons.
• Anti-patterns: Avoid common service-locator pitfalls and hidden coupling.