Kaskade

State Container for Kotlin and Android.

The name comes from cascade, a waterfall, which reflects the objective of the library to make flows easier with unidirectional data flow.

Inspired by MVI or Model View Intent.

Why Kaskade?

Lightweight - enforces unidirectional data flow without the use of external dependencies.
Modular - can be easily substituted to different implementation with or without the use of another library.
Extendable - in relation to modular and lightweight, it's important to extend the API and create user defined implementation to fit specific requirements.
Unidirectional - data flows in one direction.
Predictable - control on state changes and action triggers.
DSL - able to hide complexity in a fluent way.
Multiplatform - built for JVM, iOS, and Javascript.

Installation

Add to settings.gradle

enableFeaturePreview('GRADLE_METADATA')

Add the dependency

dependencies {
  // core module
  implementation 'dev.gumil.kaskade:core:0.x.y'
  // coroutines module
  implementation 'dev.gumil.kaskade:coroutines:0.x.y'
  // rx module
  implementation 'dev.gumil.kaskade:rx:0.x.y'
  // livedata module
  implementation 'dev.gumil.kaskade:livedata:0.x.y'
}

(Please replace x and y with the latest version numbers: )

Usage

Create the Action and State objects.

Note: objects are only used here for simplicity in real projects data classes are more appropriate

internal sealed class TestState : State {
    object State1 : TestState()
    object State2 : TestState()
    object State3 : TestState()
}

internal sealed class TestAction : Action {
    object Action1 : TestAction()
    object Action2 : TestAction()
    object Action3 : TestAction()
}

Create Kaskade with TestState.State1 as initial state

val kaskade = Kaskade.create<TestAction, TestState>(TestState.State1) {
    on<TestAction.Action1> {
        TestState.State1
    }

    on<TestAction.Action2> {
        TestState.State2
    }

    on<TestAction.Action3> {
        TestState.State3
    }
}

Adding actions to Action with parameter ActionState

on<TestAction.Action1> { actionState ->
    // do any side effects when returning a new state
    TestState.State1
}

Observing states

kaskade.onStateChanged = {
    // Do something with new state
    render(it)
}

Observing states with Emitter

kaskade.stateEmitter().subscribe {
    // Do something with new state
    render(it)
}

Executing actions

kaskade.dispatch(TestAction.Action1)

Documentation

Check out the wiki for documentation.

Some of the topics covered are:

Sample projects