在javascript中同时映射和减少数组

我有一个约1800个对象的数组，代表在一个联盟中进行的游戏。我需要一个新数组，每个团队都有一个对象，它将包括4个新字段（

赢

，

输

，

结

，和

分

）。以下是我正在使用的阵列示例：

[
  {
    "homeGoals": 2,
    "gameId": "12221",
    "homeTeam": {
      "id": "aasfdsf1",
      "teamName": "Team 1"
    },
    "awayTeam": {
      "id": "aasfdsf2",
      "teamName": "Team 2"
    },
    "id": "ggaew1",
    "awayGoals": 4
  },
  {
    "homeGoals": 5,
    "gameId": "12222",
    "homeTeam": {
      "id": "aasfdsf1",
      "teamName": "Team 1"
    },
    "awayTeam": {
      "id": "aasfdsf3",
      "teamName": "Team 3"
    },
    "id": "ggaew2",
    "awayGoals": 1
  },
  {
    "homeGoals": 4,
    "gameId": "12223",
    "homeTeam": {
      "id": "aasfdsf2",
      "teamName": "Team 2"
    },
    "awayTeam": {
      "id": "aasfdsf3",
      "teamName": "Team 3"
    },
    "id": "ggaew3",
    "awayGoals": 4
  },
  {
    "homeGoals": null,
    "gameId": "12223",
    "homeTeam": {
      "id": "aasfdsf2",
      "teamName": "Team 2"
    },
    "awayTeam": {
      "id": "aasfdsf3",
      "teamName": "Team 3"
    },
    "id": "ggaew4",
    "awayGoals": null
  }
]

下面是一个我需要的结果的示例：

 [
  {
    "id": "aasfdsf1",
    "name": "Team 1",
    "wins": 1,
    "losses": 1,
    "ties": 0,
    "points": 2 
  },
  {
    "id": "aasfdsf2",
    "name": "Team 2",
    "wins": 1,
    "losses": 0,
    "ties": 1,
    "points": 3 
  },
  {
    "id": "aasfdsf3",
    "name": "Team 3",
    "wins": 0,
    "losses": 1,
    "ties": 1,
    "points": 1 
  }
]

有些游戏尚未玩，因此

homegools

和

awayGoals

字段将为空

到目前为止，我有一个独特的球队名单，只有在比赛已经完成的地方：

const completedGames = games.filter(x => x.homeGoals !== null)
const homeTeams = [...new Set(completedGames.map(x => x['homeTeam']))];
const awayTeams = [...new Set(completedGames.map(x => x['awayTeam']))];
const teams = [...new Set([...homeTeams, ...awayTeams])]

---

我知道我需要做一些reduce函数，但是我在计算它时遇到了困难。我非常确信，如果我有一个适当的map reduce函数，我刚才做的步骤将是不相关的。任何帮助都将不胜感激

我想你正在寻找这样的东西：

const hashMapTeams = games.filter(x => x.homeGoals !== null)
.reduce((res, match)=>{
   /* do the calculations here */
   /* put the values on the res object, using res as a HashMap*/
    res["/*the home team id*/"].id = /*id value*/
    res["/*the home team id*/"].name = /*name value*/
    res["/*the home team id*/"].wins= /* the right value */;
    res["/*the home team id*/"].losses= /* the right value */;
    res["/*the home team id*/"].ties= /* the right value */;
    res["/*the home team id*/"].points= /* the right value */;

    res["/*the away team id*/"].id = /*id value*/
    res["/*the away team id*/"].name = /*name value*/
    res["/*the away team id*/"].wins= /* the right value */;
    res["/*the away team id*/"].losses= /* the right value */;
    res["/*the away team id*/"].ties= /* the right value */;
    res["/*the away team id*/"].points= /* the right value */;
 },{});

/* This will convert again the object to an array */
const arrayTeams = Object.keys(hashMapTeams).map(function (key) { return hashMapTeams[key]; });

---

我想你正在寻找这样的东西：

const hashMapTeams = games.filter(x => x.homeGoals !== null)
.reduce((res, match)=>{
   /* do the calculations here */
   /* put the values on the res object, using res as a HashMap*/
    res["/*the home team id*/"].id = /*id value*/
    res["/*the home team id*/"].name = /*name value*/
    res["/*the home team id*/"].wins= /* the right value */;
    res["/*the home team id*/"].losses= /* the right value */;
    res["/*the home team id*/"].ties= /* the right value */;
    res["/*the home team id*/"].points= /* the right value */;

    res["/*the away team id*/"].id = /*id value*/
    res["/*the away team id*/"].name = /*name value*/
    res["/*the away team id*/"].wins= /* the right value */;
    res["/*the away team id*/"].losses= /* the right value */;
    res["/*the away team id*/"].ties= /* the right value */;
    res["/*the away team id*/"].points= /* the right value */;
 },{});

/* This will convert again the object to an array */
const arrayTeams = Object.keys(hashMapTeams).map(function (key) { return hashMapTeams[key]; });

---

这可以用

flatMap

以更简单的方式表示。它不是内置在JS中，但易于实现：

let flatMap = (a, fn) => [].concat(...a.map(fn));

现在，在地图步骤中，您可以在每场游戏中发射两个“结果”对象（如果游戏不完整，则根本没有结果）：

这很容易减少：

summary = results.reduce((m, {id, r}) => {
    let e = m[id] || {};
    e[r] = (e[r] || 0) + 1;
    return Object.assign(m, {[id]: e})
}, {});

您还可以通过将赢、输和平局分别编码为1、-1、0来减少冗余，在这种情况下，映射器将变为：

results = flatMap(
    data.filter(g => g.homeGoals !== null),
    g => {
        let d = g.homeGoals - g.awayGoals;
        return [
            {id: g.homeTeam.id, r: Math.sign(+d)},
            {id: g.awayTeam.id, r: Math.sign(-d)},
        ]
    });

---

这可以用

flatMap

以更简单的方式表示。它不是内置在JS中，但易于实现：

let flatMap = (a, fn) => [].concat(...a.map(fn));

现在，在地图步骤中，您可以在每场游戏中发射两个“结果”对象（如果游戏不完整，则根本没有结果）：

这很容易减少：

summary = results.reduce((m, {id, r}) => {
    let e = m[id] || {};
    e[r] = (e[r] || 0) + 1;
    return Object.assign(m, {[id]: e})
}, {});

您还可以通过将赢、输和平局分别编码为1、-1、0来减少冗余，在这种情况下，映射器将变为：

results = flatMap(
    data.filter(g => g.homeGoals !== null),
    g => {
        let d = g.homeGoals - g.awayGoals;
        return [
            {id: g.homeTeam.id, r: Math.sign(+d)},
            {id: g.awayTeam.id, r: Math.sign(-d)},
        ]
    });

---

这将获得您想要的确切结果：

{
  "id": "aasfdsf1",
  "name": "Team 1",
  "wins": 1,
  "losses": 1,
  "ties": 0,
  "points": 2 
},

我用十进制和括号向你们展示了不止一种方法，你们可以用任何一种

let result = [];

your1800ArrayObj.map(data => {      
    let wins = data.wins ? data.wins : 0;
    let losses = data.losses ? data.losses : 0;
    let ties = data['ties'] || 0;
    let points = data['points'] || 0;

    if (data.homeGoals === null && data.awayGoals === null) {
        console.log('game not played')
        } else {
            if (data.homeGoals > data.awayGoals) {
                wins += 1
                points += 1
            } else if (data.homeGoals < data.awayGoals) {
                losses += 1
            } else {
                ties += 1
            }
        }

    result.push({
        id: data.id,
        name: data.homeTeam.teamName ,
        wins: wins,
        losses: losses,
        ties: ties,
        points: points
    })
})

return result
}

let result=[]；
your1800ArrayObj.map（数据=>{
让wins=data.wins？data.wins:0；
让损失=data.loss？data.loss:0；
设ties=data['ties']|0；
设点=数据[“点”]| | 0；
if（data.homegools==null&&data.awayGoals==null）{
console.log（'未玩游戏'）
}否则{
if（data.homeGoals>data.awayGoals）{
wins+=1
点数+=1
}else if（data.homegals

这会得到您想要的准确结果：

{
  "id": "aasfdsf1",
  "name": "Team 1",
  "wins": 1,
  "losses": 1,
  "ties": 0,
  "points": 2 
},

我用十进制和括号向你们展示了不止一种方法，你们可以用任何一种

let result = [];

your1800ArrayObj.map(data => {      
    let wins = data.wins ? data.wins : 0;
    let losses = data.losses ? data.losses : 0;
    let ties = data['ties'] || 0;
    let points = data['points'] || 0;

    if (data.homeGoals === null && data.awayGoals === null) {
        console.log('game not played')
        } else {
            if (data.homeGoals > data.awayGoals) {
                wins += 1
                points += 1
            } else if (data.homeGoals < data.awayGoals) {
                losses += 1
            } else {
                ties += 1
            }
        }

    result.push({
        id: data.id,
        name: data.homeTeam.teamName ,
        wins: wins,
        losses: losses,
        ties: ties,
        points: points
    })
})

return result
}

let result=[]；
your1800ArrayObj.map（数据=>{
让wins=data.wins？data.wins:0；
让损失=data.loss？data.loss:0；
设ties=data['ties']|0；
设点=数据[“点”]| | 0；
if（data.homegools==null&&data.awayGoals==null）{
console.log（'未玩游戏'）
}否则{
if（data.homeGoals>data.awayGoals）{
wins+=1
点数+=1
}else if（data.homegals

谢谢您的帮助！summary函数返回一个对象的对象，如何使其成为数组？我尝试将函数末尾的

{}

更改为

[]

，但返回了一个空白数组。感谢您的帮助！summary函数返回一个对象的对象，如何使其成为数组？我尝试将函数末尾的

{}

更改为

[]

，但返回了一个空白数组。