按多个属性对对象进行分组并合并数组属性

Question

在示例中，我使用 each 通过 select 字段并创建数据数组，我需要将 2 个属性 year 和 cabin 以及属性 months 是一个我想合并的数组，问题是我在获得想要的结果时遇到了一些麻烦：

JSFIDDLE：http://jsfiddle.net/tc39xu6b/2/

我得到的结果：

[
  {
    "year": "2021",
    "cabin": "1",
    "months": [
      "1",
      "2"
    ]
  },
  {
    "year": "2021",
    "cabin": "1",
    "months": [
      "4"
    ]
  },
  {
    "year": "2021",
    "cabin": "2",
    "months": [
      "1",
      "2"
    ]
  },
  {
    "year": "2022",
    "cabin": "1",
    "months": [
      "1",
      "2"
    ]
  },
  {
    "year": "2022",
    "cabin": "1",
    "months": [
      "4"
    ]
  },
  {
    "year": "2022",
    "cabin": "2",
    "months": [
      "1",
      "2"
    ]
  }
]

这就是我需要的结果：

{
  "2021": [
      {"cabin":1, "months": ["1", "2","4"]},
      {"cabin":2, "months": ["1", "2"]}
  ],
  "2022": [
      {"cabin":1, "months": ["1", "2","4"]},
      {"cabin":2, "months": ["1", "2"]}
  ]
}

Answer 1

那么，您已经找到了解决方案。

根据你所拥有的，我写了一个分组函数：

const addUnique=(arr1,arr2)=>{
    arr2.forEach(item=>arr1.includes(item) || arr1.push(item))
    return arr1;
}

const grouped= obj.reduce((groups,item)=>{
  const yearItems=(groups[item.year]||[])
  const cabinItem=yearItems.find(({cabin})=>cabin===item.cabin)
  const newCabinItem=cabinItem||{cabin:item.cabin};
  newCabinItem.months=addUnique(newCabinItem.months||[],item.months);
    
  return {
    ...groups,
    [item.year]: cabinItem 
        ? yearItems.map(yearItem =>
          yearItem.cabin === item.cabin 
            ? newCabinItem 
            : yearItem)
        : yearItems.concat([newCabinItem])
    }
},{})

你可以看到它在这里工作：http://jsfiddle.net/9huwkz5L/

Answer 2

这是一个相当标准的 group by 情况。下面的代码片段使用 reduce() 来重构您的数组，但您可以将逻辑直接放在您的函数中：http://jsfiddle.net/83st9wgh/

const input = [{ "year": "2021", "cabin": "1", "months": ["1", "2"] }, { "year": "2021", "cabin": "1", "months": ["4"] }, { "year": "2021", "cabin": "2", "months": ["1", "2"] }, { "year": "2022", "cabin": "1", "months": ["1", "2"] }, { "year": "2022", "cabin": "1", "months": ["4"] }, { "year": "2022", "cabin": "2", "months": ["1", "2"] }];

const result = input.reduce((acc, { year, cabin, months }) => {
  const yearArray = (acc[year] ??= []);

  let cIndex = yearArray.findIndex(o => o.cabin === cabin);
  if (cIndex === -1) {
    cIndex = yearArray.push({ cabin, months: [] }) - 1;
  }

  const monthsArray = yearArray[cIndex].months;
  yearArray[cIndex].months = [...new Set(monthsArray.concat(months))];

  return acc;
}, {});

console.log(JSON.stringify(result, null, 2));

按多个属性对对象进行分组并合并数组属性

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按多个属性对对象进行分组并合并数组 属性

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按多个属性对对象进行分组并合并数组属性