main.jsx

import { app } from 'hyperapp';
import h from 'hyperapp-jsx-pragma';

const AddTodo = (state) => ({
    ...state,
    value: "",
    todos: state.todos.concat(state.value),
})


const NewValue = (state, event) => ({
    ...state,
    value: event.target.value,
})

function viewFn(state) {
    console.log(state);
    return <main>
        <h1>To do list</h1>
        <input type="text" onInput={[NewValue, state.value]} />
        <ul>
        </ul>
        <button onClick={AddTodo}>New!</button>
        </main>
}

app({
    init: { todos: [], value: "" },
    view: viewFn,
    node: document.getElementById("app"),
})