action_less.kt

import kempo.Reducer
import kempo.el

data class State(
    val name: String,
    val counter: Int = 0
) {
    fun withName(name: String) = State(name, counter)
    fun withCounter(counter: Int) = State(name, counter)
}

val template = el<State, State, Unit> {
    className("my-class")
    +"Hello "
    el("button") {
        onClick { state: State -> state.withCounter(state.counter + 1) }
        text { it.name }
    }
    +" "
    text { it.counter.toString() }
}

fun main() {
    kempo.run(template, State(
        name = "Franco Small"
    ))
}

main.kt

import kempo.Reducer
import kempo.el

data class State(
    val name: String,
    val counter: Int = 0
) {
    fun withName(name: String) = State(name, counter)
    fun withCounter(counter: Int) = State(name, counter)
}

sealed class Action {
    object Increment : Action()
}

val template = el<State, Action, Unit> {
    className("my-class")
    +"Hello "
    el("button") {
        onClick { -> Action.Increment }
        text { it.name }
    }
    +" "
    text { it.counter.toString() }
}

val reducer: Reducer<State, Action> = { state, action ->
    when (action) {
        is Action.Increment -> state.withCounter(state.counter + 1)
    }
}

fun main() {
    kempo.run(template, reducer, State(
        name = "Franco Small"
    ))
}