Example — Counter

A minimal interactive widget: one integer property, two actions, one template.

Component

Kotlin

package app.brew

import org.konaframework.brew.Component

class Counter : Component() {
    var count = 0

    fun mount(start: Int = 0) {
        count = start
    }

    fun increment() { count++ }
    fun decrement() { count-- }
    fun reset() { count = 0 }

    override fun template() = """
        <div class="counter">
            <button type="button" wire:click="decrement" wire:loading.attr="disabled">−</button>
            <span wire:text="count"></span>
            <button type="button" wire:click="increment" wire:loading.attr="disabled">+</button>
            <button type="button" wire:click="reset">Reset</button>
            <span wire:loading wire:target="increment,decrement">…</span>
        </div>
    """.trimIndent()
}

Java

package app.brew;

import org.konaframework.brew.Component;

public class Counter extends Component {
    public int count = 0;

    public void mount(int start) { count = start; }
    public void increment() { count++; }
    public void decrement() { count--; }
    public void reset() { count = 0; }

    @Override
    public String template() {
        return """
            <div class="counter">
                <button type="button" wire:click="decrement" wire:loading.attr="disabled">−</button>
                <span wire:text="count"></span>
                <button type="button" wire:click="increment" wire:loading.attr="disabled">+</button>
                <button type="button" wire:click="reset">Reset</button>
            </div>
            """;
    }
}

Page

<brew:counter :start="3" />

Test

Brew.test(Counter::class.java, mapOf("start" to 3))
    .assertSet("count", 3)
    .call("increment")
    .assertSet("count", 4)
    .call("reset")
    .assertSet("count", 0)

The repo samples (samples/brew-kotlin, samples/brew-java) ship a similar counter on the welcome page.