Reaktiv

Reaktiv is a powerful MVLI (Model-View-Logic-Intent) library for Kotlin Multiplatform, designed to simplify state management and navigation in modern applications. It provides a robust architecture for building scalable and maintainable applications across various platforms.

Features

• MVLI Architecture: Implements a unidirectional data flow pattern with a distinct Logic layer for enhanced separation of concerns
• Kotlin Multiplatform: Supports Android, iOS, Desktop, and Web from a single codebase
• Type-safe Navigation: Powerful navigation system with nested graphs, deep linking, modals, and automatic backstack synthesis
• Jetpack Compose Integration: Seamless integration with Compose Multiplatform for declarative UI
• DevTools Support: Real-time debugging with state inspection and time-travel capabilities
• State Persistence: Built-in support for saving and restoring application state
• Coroutine-First: Built entirely on Kotlin Coroutines for efficient asynchronous operations

Modules

Core

The foundation of Reaktiv providing the MVLI architecture components:

• ModuleWithLogic<S, A, L> - Type-safe module definition with state, actions, and logic
• Store - Central state manager coordinating all modules
• StoreAccessor - Interface for accessing state, logic, and dispatch
• Middleware system for cross-cutting concerns (logging, analytics, etc.)
• State persistence with customizable strategies
• CustomTypeRegistrar for polymorphic serialization
• HighPriorityAction for urgent action processing
• ReaktivDebug utilities for development logging

Learn more about the Core module

Navigation

A comprehensive type-safe navigation system:

• Nested Graph Hierarchies - Organize screens into logical groups with unlimited nesting
• Screen & Modal Support - Full modal system with dimming, backdrop handling, and layering
• Deep Linking - Automatic backstack synthesis from URL paths
• Transitions - 20+ built-in transitions with custom animation support
• Screen Layouts - Graph-level scaffolds for shared UI (app bars, bottom navigation)
• Lifecycle Callbacks - onLifecycleCreated() with BackstackLifecycle for visibility tracking and cleanup
• Type-safe Parameters - Params class with typed access and serialization
• RenderLayer System - CONTENT, GLOBAL_OVERLAY, and SYSTEM layers with z-ordering
• NotFoundScreen - Configurable fallback for undefined routes

Learn more about the Navigation module

Compose

Jetpack Compose integration for reactive UI:

• StoreProvider - Provide store to Compose hierarchy
• composeState<S>() - Observe module state as Compose State
• rememberDispatcher() - Access dispatch function
• rememberLogic<M, L>() - Access typed module logic
• select<S, R>() - Derived state with custom selectors
• NavigationRender - Render navigation state with animations

Learn more about the Compose module

DevTools

Real-time debugging and state inspection:

• WebSocket-based connection to DevTools UI
• Action capture and replay
• State inspection and modification
• Time-travel debugging support
• Platform-aware middleware integration

Getting Started

Add the dependencies to your project:

// build.gradle.kts
dependencies {
    implementation("io.github.syrou:reaktiv-core:<version>")
    implementation("io.github.syrou:reaktiv-navigation:<version>")
    implementation("io.github.syrou:reaktiv-compose:<version>")

    // Optional: DevTools support
    implementation("io.github.syrou:reaktiv-devtools:<version>")
}

Quick Example

Define a Module

@Serializable
data class CounterState(val count: Int = 0) : ModuleState

sealed class CounterAction : ModuleAction(CounterModule::class) {
    data object Increment : CounterAction()
    data object Decrement : CounterAction()
    data class SetCount(val value: Int) : CounterAction()
}

class CounterLogic(private val storeAccessor: StoreAccessor) : ModuleLogic<CounterAction>() {

    suspend fun incrementDelayed() {
        delay(1000)
        storeAccessor.dispatch(CounterAction.Increment)
    }

    suspend fun fetchAndSetCount() {
        val count = api.fetchCount()
        storeAccessor.dispatch(CounterAction.SetCount(count))
    }
}

object CounterModule : ModuleWithLogic<CounterState, CounterAction, CounterLogic> {
    override val initialState = CounterState()

    override val reducer: (CounterState, CounterAction) -> CounterState = { state, action ->
        when (action) {
            is CounterAction.Increment -> state.copy(count = state.count + 1)
            is CounterAction.Decrement -> state.copy(count = state.count - 1)
            is CounterAction.SetCount -> state.copy(count = action.value)
        }
    }

    override val createLogic: (StoreAccessor) -> CounterLogic = { CounterLogic(it) }
}

Create the Store

val navigationModule = createNavigationModule {
    rootGraph {
        startScreen(HomeScreen)
        screens(ProfileScreen, SettingsScreen)

        graph("auth") {
            startScreen(LoginScreen)
            screens(SignUpScreen)
        }
    }
    notFoundScreen(NotFoundScreen)
}

val store = createStore {
    module(CounterModule)
    module(navigationModule)
    middlewares(loggingMiddleware)
    coroutineContext(Dispatchers.Default)
}

Use in Compose

@Composable
fun App() {
    StoreProvider(store) {
        NavigationRender(modifier = Modifier.fillMaxSize())
    }
}

@Composable
fun CounterScreen() {
    val state by composeState<CounterState>()
    val dispatch = rememberDispatcher()
    val logic = rememberLogic<CounterModule, CounterLogic>()
    val scope = rememberCoroutineScope()

    Column {
        Text("Count: ${state.count}")

        Button(onClick = { dispatch(CounterAction.Increment) }) {
            Text("Increment")
        }

        Button(onClick = { scope.launch { logic.incrementDelayed() } }) {
            Text("Increment Delayed")
        }
    }
}

Navigate

// Using the navigation DSL
scope.launch {
    store.navigation {
        navigateTo("profile") {
            putString("userId", "123")
        }
    }
}

// Type-safe navigation
scope.launch {
    store.navigation {
        navigateTo<ProfileScreen> {
            put("user", userObject)
        }
    }
}

// Deep link with backstack synthesis
scope.launch {
    store.navigation {
        navigateTo("auth/signup/verify", synthesizeBackstack = true)
    }
}

// Pop with fallback for deep links
scope.launch {
    store.navigation {
        popUpTo("home", inclusive = false, fallback = "root")
    }
}

Architecture Overview

┌─────────────────────────────────────────────────────────────┐
│                         Store                                │
│  ┌─────────────┐  ┌─────────────┐  ┌─────────────────────┐  │
│  │   Module A  │  │   Module B  │  │  NavigationModule   │  │
│  │  ┌───────┐  │  │  ┌───────┐  │  │  ┌───────────────┐  │  │
│  │  │ State │  │  │  │ State │  │  │  │ NavigationState│  │  │
│  │  └───────┘  │  │  └───────┘  │  │  └───────────────┘  │  │
│  │  ┌───────┐  │  │  ┌───────┐  │  │  ┌───────────────┐  │  │
│  │  │ Logic │  │  │  │ Logic │  │  │  │NavigationLogic│  │  │
│  │  └───────┘  │  │  └───────┘  │  │  └───────────────┘  │  │
│  └─────────────┘  └─────────────┘  └─────────────────────┘  │
│                                                              │
│  ┌────────────────────────────────────────────────────────┐ │
│  │                    Middleware Chain                     │ │
│  │  Logging → Analytics → DevTools → ... → Reducer        │ │
│  └────────────────────────────────────────────────────────┘ │
└─────────────────────────────────────────────────────────────┘
                              │
                              ▼
┌─────────────────────────────────────────────────────────────┐
│                      Compose UI Layer                        │
│  ┌─────────────┐  ┌─────────────┐  ┌─────────────────────┐  │
│  │ composeState│  │rememberLogic│  │  NavigationRender   │  │
│  └─────────────┘  └─────────────┘  └─────────────────────┘  │
└─────────────────────────────────────────────────────────────┘

Documentation

• Core Module Documentation
• Navigation Module Documentation
• Compose Module Documentation

License

Reaktiv is released under the Apache License Version 2.0. See the LICENSE file for details.