遍历对象数组并创建一个新对象

debugcn 发表于 Dev

坦乔尔·拉吉

我有一组这样的对象：

[
  {id:1,val: 5,name: 'Josh'},
  {id:2,val: 7,name: 'John'},
  {id:3,val: 6,name:'mike'},
  {id:4,val: 7,name: 'Andy'},
  {id:5,val: 8,name: 'Andrew'},
  {id:6,val: 7,name: 'Dave'}
]

我希望所有 id 都在一个 val 字段相同的数组中，并从对象数组中删除相似的对象

[
  {id:1,val: 5,name: 'Josh'},
  {id:3,val: 6,name: 'mike'},
  {id:5,val: 8,name: 'Andrew'},
  {id:[6,4,2],val: 7,name: ['Dave','Andy','John']}
]

海鸥

@Tanjore，更好的是您尝试按如下方式在对象内组织您的 id。

所有具有值的 id5都1在这里 so {'5': [1]}。

所有具有值的 id6都3在这里 so {'3': [3]}。

所有具有值的 id7都2, 3, 4在这里 so {'7': [2, 3, 4]}。

...

我们可以有一个与此类似的对象。

让我们在Node REPL上创建上述对象。

> var arr = [
...   {id:1,val: 5,name: 'Josh'},
...   {id:2,val: 7,name: 'John'},
...   {id:3,val: 6,name:'mike'},
...   {id:4,val: 7,name: 'Andy'},
...   {id:5,val: 8,name: 'Andrew'},
...   {id:6,val: 7,name: 'Dave'}
... ]
undefined
>
> var obj = {}
undefined
>
> arr.forEach((item) => {
... if (obj[item['val']] === undefined) {
..... obj[item['val']] = [item['id']];
..... } else {
..... obj[item['val']].push(item['id']);
..... }
... })
undefined
>
> obj
{ '5': [ 1 ], '6': [ 3 ], '7': [ 2, 4, 6 ], '8': [ 5 ] }
>
> JSON.stringify(obj, undefined, 4)
'{\n    "5": [\n        1\n    ],\n    "6": [\n        3\n    ],\n    "7": [\n        2,\n        4,\n        6\n    ],\n    "8": [\n        5\n    ]\n}'
>
> console.log(JSON.stringify(obj, undefined, 4))
{
    "5": [
        1
    ],
    "6": [
        3
    ],
    "7": [
        2,
        4,
        6
    ],
    "8": [
        5
    ]
}
undefined
>

最后，您可以根据上述概念获得您想要的以下数组。

[
    {
        "id": 1,
        "val": 5,
        "name": "Josh"
    },
    {
        "id": 3,
        "val": 6,
        "name": "mike"
    },
    {
        "id": [
            2,
            4,
            6
        ],
        "val": 7,
        "name": [
            "John",
            "Andy",
            "Dave"
        ]
    },
    {
        "id": 5,
        "val": 8,
        "name": "Andrew"
    }
]

检查下面的代码，它为您提供了您想要的数组。

// Input array
var arr = [
    {id:1,val: 5,name: 'Josh'},
    {id:2,val: 7,name: 'John'},
    {id:3,val: 6,name:'mike'},
    {id:4,val: 7,name: 'Andy'},
    {id:5,val: 8,name: 'Andrew'},
    {id:6,val: 7,name: 'Dave'}
]

// Empty array which we'll use to get our result and easily find the objects with similar values for 'val'
var obj = {};

arr.forEach((item) => {
    if (obj[item['val']] === undefined) {
        obj[item['val']] = item;
    } else {
        var id = obj[item['val']]['id'];
        var name = obj[item['val']]['name'];

        if(typeof id === 'number'){
            obj[item['val']]['id'] = [id, item['id']];
            obj[item['val']]['name'] = [name, item['name']];
        } else { // 'object'
            obj[item['val']]['id'].push(item['id']);
            obj[item['val']]['name'].push(item['name']);
        }
    }
})


var newArr = Object.values(obj);
// console.log(newArr);

// Pretty printing newArr
console.log(JSON.stringify(newArr, undefined, 4));

/*
    [
        {
            "id": 1,
            "val": 5,
            "name": "Josh"
        },
        {
            "id": 3,
            "val": 6,
            "name": "mike"
        },
        {
            "id": [
                2,
                4,
                6
            ],
            "val": 7,
            "name": [
                "John",
                "Andy",
                "Dave"
            ]
        },
        {
            "id": 5,
            "val": 8,
            "name": "Andrew"
        }
    ]
*/

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