List and Isolate 3 Items in Cycle.js

Question

As a newbie i am trying to make List with 3 Items in Cycle.js. But code has bugs. I made jsbin and placed code below as well

http://jsbin.com/labonut/10/edit?js,output

Problem: when i click on last checkbox, it adds new checkbox (which i did't want), and the old one does not change it's "ON/off" label. Also all except last one, not react at all. What am i doing wrong?

const xs = xstream.default;
const {div, span, input, label, makeDOMDriver} = CycleDOM;

function List(sources) {

  sources.DOM
  var vdom$ = xs.fromArray([
    {text: 'Hi'},
    {text: 'My'},
    {text: 'Ho'}
  ])
    .map(x => isolate(ListItem)({Props: xs.of(x), DOM: sources.DOM}))
    .map(x => x.DOM)
    .flatten()
    .fold((x, y) => x.concat([y]), [])
    .map(x => div('.list', x));

  return {
    DOM: vdom$
  }
}

function ListItem(sources) {
  const domSource = sources.DOM;
  const props$ = sources.Props;

  var newValue$ = domSource
    .select('.checker')
    .events('change')
    .map(ev => ev.target.checked);

  var state$ = props$
    .map(props => newValue$
      .map(val => ({
        checked: val,
        text: props.text
      }))
      .startWith(props)
    )
    .flatten();

  var vdom$ = state$
      .map(state => div('.listItem',[
        input('.checker',{attrs: {type: 'checkbox', id: 'toggle'}}),
        label({attrs: {for: 'toggle'}}, state.text),
        " - ",
        span(state.checked ? 'ON' : 'off')
      ]));
  return {
    DOM: vdom$
  }
}


Cycle.run(List, {
  DOM: makeDOMDriver('#app')
});

Answer 1

A little shorter variant.

1st line, get Items Dom streams array.

2nd line, then combine streams into one stream and wrap elements into parent div

function List(sources) {

  var props = [
    {text: 'Hi'},
    {text: 'My'},
    {text: 'Ho'}
  ];

  var items = props.map(x => isolate(ListItem)({Props: xs.of(x), DOM: sources.DOM}).DOM);

  var vdom$ = xs.combine(...items).map(x => div('.list', x));

  return {
    DOM: vdom$
  }
}

Answer 2

Inspired by Vladimir's answer here's an "old school" variation of his answer and an improvement on my original answer:

function List(sources) {

  const props = [
    {text: 'Hi'},
    {text: 'My'},
    {text: 'Ho'}
  ];

  var items = props.map(x => isolate(ListItem)({Props: xs.of(x), DOM: sources.DOM}).DOM);

  const vdom$ = xs.combine.apply(null, items)
    .map(x => div('.list', x));

  return {
    DOM: vdom$
  };
}

Old school JSBin demo

---

(Original answer.)

It appears the problem is in your List function. Frankly I don't know the reason, but have worked out another solution:

function List(sources) {

  const props = [
    {text: 'Hi'},
    {text: 'My'},
    {text: 'Ho'}
  ];

  function isolateList (props) {
    return props.reduce(function (prev, prop) {
      return prev.concat(isolate(ListItem)({Props: xs.of(prop), DOM: sources.DOM}).DOM);
    }, []);
  }

  const vdom$ = xs.combine.apply(null, isolateList(props))
    .map(x => div('.list', x));

  return {
    DOM: vdom$
  };
}

JSBin demo

One difference here is I'm not streaming the items in the props object. Rather I'm passing the array to a function that reduces the props to an array of list item vdom streams, then applying that array to the xstream combine factory.