培根更新屬性相互依賴循環引入總線

Question

我有兩個可能相互依賴的屬性，所以我介紹了一個總線：

let esDealOne1 = Bacon.later(0, true);
let esDealOne2 = Bacon.later(1000, true);


let bHanging = new Bacon.Bus();

let esSetCards = bHanging.filter(_ => _.cards);

let pHanging = HangingStateProperty(esSetCards);

let pDrawer = DrawerProperty(bHanging, esDealOne1);

let pStacks = [
  StackProperty(0, esDealOne2, pHanging),
];

function HangingStateProperty(esSetCards) {
  let setCards = (_, cards) => {
    return { ..._, ...cards };
  };

  return Bacon.update({},
                      [esSetCards, setCards]);
}

function DrawerProperty(bHanging, esDealOne1) {
    let dealOne1 = (_) => {
        let card = _.usefulProperty;
        bHanging.push({ cards: [card] });
        return _; };

    return Bacon.update({},
        [esDealOne1, dealOne1]);
}

function StackProperty(n, esAllDealOne2, pHanging) {
  let esDealOne2 = esAllDealOne2.filter(_ => _.i === n);

  let dealOne2 = (_, {i}, hangingState) => {
    let cards = hangingState.cards;

    _.property = cards;

    return _;
  };

  return Bacon.update({},
                      [esDealOne2, pHanging, dealOne2]);
}

我怎樣才能擺脫這輛公共汽車？

Answer 1

很難移除總線，相反這會簡化總線的使用：

export function SyncBus() {
  let bus = this.bus = new Bacon.Bus();

  this.assign = pBase => {
    pBase.onValue(_ => bus.push(_));
  };
}

用法：

  let bDrawer = new SyncBus();

    // don't forget `toProperty` otherwise gets old values
  let pDragCardsDrawEarly = bDrawer
      .bus
      .map(_ => _.extra)
      .filter(_ => _.dragcards)
      .map(_ => ({ dragcards: _.dragcards }))
      .toProperty();

  let pDrawer = OwnerProperty({});
  bDrawer.assign(pDrawer);