Cycle.js: text input and a button, latest text is assigned to result on button click

main.js

import {run} from '@cycle/run';
import {makeDOMDriver, div, button, br, input} from '@cycle/dom';
import xs from 'xstream';
import sampleCombine from 'xstream/extra/sampleCombine';

function main (sources) {
  const click$ = sources.DOM.select('.button').events('click').startWith(false);
  const input$ = sources.DOM.select('.input').events('input');
  const text$ = input$.map(ev => ev.target.value).startWith('');
  const combined$ = click$.compose(sampleCombine(text$));
  const result$ = combined$.map(([click, text]) => text);

  return {
    DOM: result$.map(result =>
      div([
        input('.input', {type: 'text'}),
        button('.button', 'Click Me'),
        br(), br(),
        result ? 'Result: ' + result : ''
      ])
    )
  };
}

const drivers = {
  DOM: makeDOMDriver('.app')
}

run(main, drivers);