javascript - RxJS 的循环依赖。孢子建模

Question

我尝试使用 RxJS 来建模一些游戏。但我发现循环依赖存在一些问题。因此，我将游戏简化为简单的模拟(我只留下了“移动” Action )。你可以在下面找到代码(我省略了一些部分，你可以找到 the repo here )

const rx = require('rx')
const math = require('mathjs')
const _ = require('underscore')

const FIELD_SIZE = 10

const ctx = require('axel');

let getInitialState = () => {
  return {
    size: FIELD_SIZE,
    people: [
      { x: 0, y: 0 },
      { x: 9, y: 9 },
      { x: 5, y: 5 }
    ]
  }
}

var drawWorld = ({size, people}) => {
  // draw world logic
}


let getMove = (index)=> {
  let [xOffset, yOffset] = [[0,1], [1,0]][math.pickRandom([0, 1])]
  let direction = math.pickRandom([-1, 1])
  return (state) => {
    let {people} = state
    let p = people[index]
    people[index] = {
      x: math.max(
          0,
          math.min(p.x + xOffset * direction, FIELD_SIZE-1)),
      y: math.max(
          0,
          math.min(p.y + yOffset * direction, FIELD_SIZE-1))
    }
    return _.extend({}, state, {people})
  }
}

var POOL = []

var produceActions = (state) => {
  _.range(state.people.length).forEach((i) => {
    POOL.push(getMove(i))
  })
}

var stateObservable = rx.Observable
  .interval(100)
  .timeInterval()
  .map(()=> {
    var x = POOL.slice()
    POOL.splice(0, POOL.length)
    return x
  })
  .scan(
      (state, ops) => ops.reduce(
        (st, o) => o(st),
        state
      ),
      getInitialState()
  )

stateObservable.subscribe(drawWorld)
stateObservable.tap(produceActions).subscribe()

有没有办法重写这个依赖全局变量的丑陋的“productActions”部分？ 就像 @user3743222 答案中建议的那样

Answer 1

这个问题已经在这里讨论过很多次了。

我可以提到的三种方式(可能是其他方式):

• 使用主语
  • How to handle circularly dependent observables in RxJS?
• 使用展开
  • Feedback loop without Subject in RX
  • RxJs: How to loop based on state of the observable?
  • RxJS, how to poll an API to continuously check for updated records using a dynamic timestamp
• 使用cycle.js (如果你熟悉RxJS，学习曲线很小，如果你做了很多游戏，可能是值得的)