JavaScript 对象数组 - 基于嵌套对象从数组中删除重复对象答案

【问题标题】：JavaScript array of objects - remove duplicate objects from an array based on nested objectJavaScript 对象数组 - 基于嵌套对象从数组中删除重复对象
【发布时间】：2020-04-15 16:47:32
【问题描述】：

我有一个包含嵌套类别对象的对象数组（见下文）。我想删除重复的对象（基于“objectID”）并创建一个新数组，其中仅包含具有更多嵌套“hierarchicalCategories”键值对的对象

const objectsArray = [

{
  "objectID": 1234,
  "hierarchicalCategories": {
    "lvl0": "Women's",
    "lvl1": "Women's > Shirts",
    "lvl2": "Women's > Shirts > Tees"
  }
},
{
  "objectID": 5678,
  "hierarchicalCategories": {
    "lvl0": "Men's"
  }
},
{
  "objectID": 1234,
  "hierarchicalCategories": {
    "lvl0": "Women's"
  }
},
{
  "objectID": 5678,
  "hierarchicalCategories": {
    "lvl0": "Men's",
    "lvl1": "Men's > Shoes"
  }
}

]

所以预期的结果如下所示：最终数组将过滤重复项并保留每个对象的一个实例...“objectID”：1234 个实例，其中“hierarchicalCategories”最多为“lvl2”和“objectID” : 5678 个实例，其中 "hierarchicalCategories" 达到 "lvl1"

const newArray = [

{
  "objectID": 1234,
  "hierarchicalCategories": {
    "lvl0": "Women's",
    "lvl1": "Women's > Shirts",
    "lvl2": "Women's > Shirts > Tees"
  }
},
{
  "objectID": 5678,
  "hierarchicalCategories": {
    "lvl0": "Men's",
    "lvl1": "Men's > Shoes"
  }
}

]

我有这个函数，它适用于基于过滤重复 objectID 的新数组，但我不确定如何创建逻辑以使对象具有更多“hierarchicalCategories”键值对。

     const newArray = Array.from(new Set(objectsArray.map(a => a.objectID)))
                .map(objectID => {
                    return objectsArray.find(a => a.objectID === objectID)
         })

【问题讨论】：

什么不起作用？请添加您的代码。
@NinaScholz 我更新了我的答案以包含一个用于过滤重复 objectID 的函数，但我不确定如何根据嵌套对象中“hierarchicalCategories”的数量进行过滤

标签： javascript arrays

【解决方案1】：

您可以使用Map 并将类别分配到同一组。

const
    objectsArray = [{ objectID: 1234, hierarchicalCategories: { lvl0: "Women's", lvl1: "Women's > Shirts", lvl2: "Women's > Shirts > Tees" } }, { objectID: 5678, hierarchicalCategories: { lvl0: "Men's" } }, { objectID: 1234, hierarchicalCategories: { lvl0: "Women's" } }, { objectID: 5678, hierarchicalCategories: { lvl0: "Men's", lvl1: "Men's > Shoes" } }],
    result = Array.from(objectsArray
        .reduce((m, o) => {
            if (m.has(o.objectID)) {
                Object.assign(m.get(o.objectID).hierarchicalCategories, o.hierarchicalCategories);
                return m;
            }
            return m.set(o.objectID, o);            
        }, new Map)
       .values()
    );

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

一种更短的方法，直接收集类别并从收集的部分构建新对象。

const
    objectsArray = [{ objectID: 1234, hierarchicalCategories: { lvl0: "Women's", lvl1: "Women's > Shirts", lvl2: "Women's > Shirts > Tees" } }, { objectID: 5678, hierarchicalCategories: { lvl0: "Men's" } }, { objectID: 1234, hierarchicalCategories: { lvl0: "Women's" } }, { objectID: 5678, hierarchicalCategories: { lvl0: "Men's", lvl1: "Men's > Shoes" } }],
    result = Array.from(
        objectsArray.reduce((m, { objectID: id, hierarchicalCategories: o }) => 
            m.set(id, Object.assign((m.get(id) || {}), o)), new Map),
       ([objectID, hierarchicalCategories]) => ({ objectID, hierarchicalCategories })
    );

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

【讨论】：

【解决方案2】：

使用.sort() 和.filter() 从最高级别到最低级别排序并进行过滤，以便只有最高级别的级别在新数组中。

const objectsArray = [

  {
    "objectID": 1234,
    "hierarchicalCategories": {
      "lvl0": "Women's",
      "lvl1": "Women's > Shirts",
      "lvl2": "Women's > Shirts > Tees"
    }
  },
  {
    "objectID": 5678,
    "hierarchicalCategories": {
      "lvl0": "Men's"
    }
  },
  {
    "objectID": 1234,
    "hierarchicalCategories": {
      "lvl0": "Women's"
    }
  },
  {
    "objectID": 5678,
    "hierarchicalCategories": {
      "lvl0": "Men's",
      "lvl1": "Men's > Shoes"
    }
  }
]
const newArray = objectsArray.sort((a, b) => Object.keys(b.hierarchicalCategories).length - Object.keys(a.hierarchicalCategories).length).filter((v, i, a) => i === a.findIndex(e => e.objectID === v.objectID));

console.log(newArray);

.as-console-wrapper {
  max-height: 100% !important;
  top: 0;
}

【讨论】：

【解决方案3】：

const shouldAdd = (item, target) => {
  if (!target[item.objectID]) return true;
  if (target[item.objectID] && !target[item.objectID].hierarchicalCategories && item.hierarchicalCategories) return true;
  if (target[item.objectID] && target[item.objectID].hierarchicalCategories && item.hierarchicalCategories && Object.keys(target[item.objectID].hierarchicalCategories).length < Object.keys(item.hierarchicalCategories).length) return true;
}

let newObjectsArray = {}
objectsArray.forEach((obj) => {
  if (shouldAdd(obj, newObjectsArray)) {
    newObjectsArray[obj.objectID] = obj
  }
})

console.log(Object.values(newObjectsArray)); //Object.values(newObjectsArray) should contain what you want

【讨论】：

【解决方案4】：

const objectsArray = [

{
  "objectID": 1234,
  "hierarchicalCategories": {
    "lvl0": "Women's",
    "lvl1": "Women's > Shirts",
    "lvl2": "Women's > Shirts > Tees"
  }
},
{
  "objectID": 5678,
  "hierarchicalCategories": {
    "lvl0": "Men's"
  }
},
{
  "objectID": 1234,
  "hierarchicalCategories": {
    "lvl0": "Women's"
  }
},
{
  "objectID": 5678,
  "hierarchicalCategories": {
    "lvl0": "Men's",
    "lvl1": "Men's > Shoes"
  }
}

]

var result_arr = objectsArray.reduce((acc, curr) => {
    const existing_obj = acc.find(item => item.objectID === curr.objectID);
    if (existing_obj) {
        if (Object.keys(curr.hierarchicalCategories).length > Object.keys(existing_obj.hierarchicalCategories).length)
        existing_obj.hierarchicalCategories = {...curr.hierarchicalCategories };
    } else {
        acc.push(curr);
    }
    return acc;
}, []);

console.log(result_arr)

【讨论】：