ReactiveState

Kotlin Multiplatform ViewModels and reactive state management based on StateFlow.

See the ReactiveState documentation for more details.

Examples

Map/transform a StateFlow:

val number = MutableStateFlow(0)
val doubledNumber: StateFlow<Int> = derived { 2 * get(number) }

Collect two StateFlows (just collect without transforming):

val base = MutableStateFlow(0)
val extra = MutableStateFlow(0)
autoRun {
    if (get(base) + get(extra) > 10) {
        alert("You're flying too high")
    }
}

Multiplatform ViewModels with automatic error handling and loading indicator tracking:

class ExampleViewModel(scope: CoroutineScope, val repository: ExampleRepository) : ReactiveViewModel(scope) {
    val inputFieldValue = MutableStateFlow("default")

    fun submit() {
        // The launch function automatically catches exceptions and increments/decrements the loading indicator.
        // This way you can't forget the fundamentals that have to be always handled correctly.
        launch {
            repository.submit(inputFieldValue.value)
        }
    }
}

Intercept MutableStateFlow:

public val state: MutableStateFlow<String> = MutableStateFlow("value").afterUpdate {
    // This is called every time after someone sets `state.value = ...`
}

Convert StateFlow to MutableStateFlow:

val readOnly: StateFlow<Int> = getSomeStateFlow()
val mutable: MutableStateFlow<Int> = readOnly.toMutable { value: Int ->
    // This is executed whenever someone sets `mutable.value = ...`.
}

See the ReactiveState documentation for more details.

Supported platforms

• Android
• JVM
• All native (including iOS)
• JS
• WASM

Installation

Add the package to your build.gradle's dependencies {}:

dependencies {
    // Add the BOM using the desired ReactiveState version
    api platform("com.ensody.reactivestate:reactivestate-bom:VERSION")
    // Leave out the version number from now on.

    // Jetpack Compose integration
    implementation "com.ensody.reactivestate:reactivestate-compose"

    // Android-only integration for Activity/Fragment
    implementation "com.ensody.reactivestate:reactivestate-android"

    // UI-independent core APIs
    implementation "com.ensody.reactivestate:reactivestate-core"

    // Utils for unit tests that want to use coroutines
    implementation "com.ensody.reactivestate:reactivestate-core-test"

    // Android-only unit test extensions
    implementation "com.ensody.reactivestate:reactivestate-android-test"
}

Also, make sure you've integrated the Maven Central repo, e.g. in your root build.gradle:

subprojects {
    repositories {
        // ...
        mavenCentral()
        // ...
    }
}

License

Copyright 2025 Ensody GmbH, Waldemar Kornewald

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.