ES6：在数组中查找包含对象 ID 的对象，并合并总计 [重复]

Question

给定一个这样的对象数组：

[
  {
    playerId: 1,
    playerName: "Cooper",
    assists: 1,
    points: 5,
  },
  {
    playerId: 1,
    playerName: "Cooper",
    assists: 3,
    points: 2,
  },
  {
    playerId: 2,
    playerName: "Tom",
    assists: 1,
    points: 3,
  },
  {
    playerId: 2,
    playerName: "Tom",
    assists: 3,
    points: 1,
  },
  {
    playerId: 3,
    playerName: "Shelby",
    assists: 2,
    points: 7,
  },
  {
    playerId: 3,
    playerName: "Shelby",
    assists: 1,
    points: 2,
  },
]

有没有办法使用 ES6 在对象数组中找到匹配的对象键（本例中为 playerId），然后为这些匹配组合其他对象键（助攻和点），因此最终数组看起来像这样：

[
  {
    playerId: 1,
    playerName: "Cooper",
    assists: 4,
    points: 7,
  },
  {
    playerId: 2,
    playerName: "Tom",
    assists: 4,
    points: 4,
  },
  {
    playerId: 3,
    playerName: "Shelby",
    assists: 3,
    points: 9,
  },
]

Answer 1

您可以使用Array.prototype.reduce() 来累积属性，通过减少到首先以playerId 作为键的对象进行跟踪，然后使用Object.values() 按预期取回数组。

let arrIn = [{"playerId":1,"playerName":"Cooper","assists":1,"points":5},{"playerId":1,"playerName":"Cooper","assists":3,"points":2},{"playerId":2,"playerName":"Tom","assists":1,"points":3},{"playerId":2,"playerName":"Tom","assists":3,"points":1},{"playerId":3,"playerName":"Shelby","assists":2,"points":7},{"playerId":3,"playerName":"Shelby","assists":1,"points":2}];

let arrOut = Object.values(arrIn.reduce((acc, current) => {
  let base = acc[current.playerId];
  if (!base) {
    // if we have not processed an object with this playerId yet,
    // simply copy the current object
    acc[current.playerId] = current;
  } else {
    // otherwise, increase the properties
    base.assists += current.assists;
    base.points += current.points;
  }

  return acc;
}, {}));
console.log(arrOut);