JavaScript 如何根据类型分组处理数据

Question

得到一组数据，想要根据商店id(storeId)来分组处理改数据，请教一下有没有更好的方法？？？

Answer 1

function transformData(arr, key) {
  const result = {}
  arr.forEach(item => {
    if (!result[item[key]]) {
      result[item[key]] = {
        [key]: item[key],
        goodList: [item],
      }
    } else {
      result[item[key]].goodList.push(item)
    }
  })
  return Object.values(result)
}
transformData(arr, 'storeId')

可以考虑一下lodash的groupBy

Answer 2

写了一个reduce版本的，供参考

const groupGoodListByStoreId = (arr) => arr.reduce((info, item) => {
  const { keyPosition, result } = info;
  const { storeId } = item;
  if (!(item.storeId in keyPosition)) {
    result.push({ storeId, goodsList: [] });
    keyPosition[storeId] = result.length - 1;
  }
  result[keyPosition[storeId]].goodsList.push(item);
  return { keyPosition, result };
}, { keyPosition: {}, result: [] });

待转换的数据

const goodList = [
  { id: 1, storeId: 1 },
  { id: 2, storeId: 2 },
  { id: 3, storeId: 1 }
];

执行转换函数

const { result } = groupGoodListByStoreId(goodList);
console.log(result);

转换后的结果

[
  {
    "storeId": 1,
    "goodsList": [
      {
        "id": 1,
        "storeId": 1
      },
      {
        "id": 3,
        "storeId": 1
      }
    ]
  },
  {
    "storeId": 2,
    "goodsList": [
      {
        "id": 2,
        "storeId": 2
      }
    ]
  }
]