时间戳

首页 > 解决方案 > 如何使用 lodash 按嵌套属性分组？

javascript - 如何使用 lodash 按嵌套属性分组？

问题描述

我有对象数组

{
    "work": [{
            "_id": "5c80c5c00c253823fc443337",
            "start": "2019-01-01T18:30:00.000Z",
            "end": "2019-01-02T18:30:00.000Z",
            "employee": {
                "_id": "5c80c16e0c253823fc44332a",
                "status": "active",
                "location": "Chennai",
                "contact_number": "1234567890"
            },
            "allocation": 30
        },
        {
            "_id": "5c80c5ef0c253823fc443339",
            "start": "2018-12-31T18:30:00.000Z",
            "end": "2019-09-30T18:30:00.000Z",
            "employee": {
                "_id": "5c80c16e0c253823fc44332a",
                "status": "active",
                "location": "Chennai",
                "contact_number": "1234567890"
            },
            "allocation": 100
        },
        {
            "_id": "5c80c60b0c253823fc44333a",
            "start": "2018-12-31T18:30:00.000Z",
            "end": "2020-10-07T18:30:00.000Z",
            "employee": {
                "_id": "5c80c16e0c253823fc44332a",
                "status": "active",
                "location": "Chennai",
                "contact_number": "1234567890"
            },
            "allocation": 25
        },
        {
            "_id": "5c80c65e0c253823fc44333b",
            "start": "2019-01-01T18:30:00.000Z",
            "end": "2019-10-04T18:30:00.000Z",
            "employee": {
                "_id": "5c80c1940c253823fc44332b",
                "status": "active",
                "location": "Chennai",
                "contact_number": "1234567890"
            },
            "allocation": 50
        },
        {
            "_id": "5c80c7240c253823fc44333f",
            "start": "2018-12-31T18:30:00.000Z",
            "end": "2019-10-09T18:30:00.000Z",
            "employee": {
                "_id": "5c80c26e0c253823fc44332e",
                "status": "active",
                "location": "Chennai",
                "contact_number": "1234567890"
            },
            "allocation": 25
        }
    ]
}

我需要将它们转换为

[{
    "_id": "5c80c16e0c253823fc44332a",
    "status": "active",
    "location": "Chennai",
    "contact_number": "1234567890",
    "work": [{
        "_id": "5c80c5c00c253823fc443337",
        "start": "2019-01-01T18:30:00.000Z",
        "end": "2019-01-02T18:30:00.000Z",
        "allocation": 30
    }, {
        "_id": "5c80c5ef0c253823fc443339",
        "start": "2018-12-31T18:30:00.000Z",
        "end": "2019-09-30T18:30:00.000Z",
        "allocation": 100
    }, {
        "_id": "5c80c60b0c253823fc44333a",
        "start": "2018-12-31T18:30:00.000Z",
        "end": "2020-10-07T18:30:00.000Z",
        "allocation": 25
    }]
}, {
    "_id": "5c80c1940c253823fc44332b",
    "status": "active",
    "location": "Chennai",
    "contact_number": "1234567890",
    "work": [{
        "_id": "5c80c65e0c253823fc44333b",
        "start": "2019-01-01T18:30:00.000Z",
        "end": "2019-10-04T18:30:00.000Z",
        "allocation": 50
    }]
}, {
    "_id": "5c80c26e0c253823fc44332e",
    "status": "active",
    "location": "Chennai",
    "contact_number": "1234567890",
    "work": [{
        "_id": "5c80c7240c253823fc44333f",
        "start": "2018-12-31T18:30:00.000Z",
        "end": "2019-10-09T18:30:00.000Z",
        "allocation": 25
    }]
}]

我通过部分使用 lodash 和 vanilla js 完成了它，它工作得很好。但可读性完全不好。我想单独使用 lodash 来实现这一点。有什么帮助吗？

let ids: any = groupBy(this.project.work, function (res) {
    return res.employee._id;
});

for (let id in ids) {
    let tmp = [];
    let employee_added = false;
    ids[id].map((work) => {
        if (!employee_added) {
            tmp = work.employee;
            tmp['work'] = [];
            employee_added = true;
        }
        delete work.employee;
        tmp['work'].push(work);
    })

    this.employees.push(tmp);
}

console.log(this.employees);

标签： javascriptarraystypescriptgroupinglodash

解决方案

希望这是您正在寻找的。

  1. 首先将其分组employee_.id
  2. 然后映射每个组，取第一个员工（因为每个组必须有一个条目）
  3. 然后将每个组的所有其他成员（并获取外部部分）映射到work （除了员工对象之外的所有内容）

这是下面的示例：

let works = [{"_id":"5c80c5c00c253823fc443337","start":"2019-01-01T18:30:00.000Z","end":"2019-01-02T18:30:00.000Z","employee":{"_id":"5c80c16e0c253823fc44332a","status":"active","location":"Chennai","contact_number":"1234567890"},"allocation":30},{"_id":"5c80c5ef0c253823fc443339","start":"2018-12-31T18:30:00.000Z","end":"2019-09-30T18:30:00.000Z","employee":{"_id":"5c80c16e0c253823fc44332a","status":"active","location":"Chennai","contact_number":"1234567890"},"allocation":100},{"_id":"5c80c60b0c253823fc44333a","start":"2018-12-31T18:30:00.000Z","end":"2020-10-07T18:30:00.000Z","employee":{"_id":"5c80c16e0c253823fc44332a","status":"active","location":"Chennai","contact_number":"1234567890"},"allocation":25},{"_id":"5c80c65e0c253823fc44333b","start":"2019-01-01T18:30:00.000Z","end":"2019-10-04T18:30:00.000Z","employee":{"_id":"5c80c1940c253823fc44332b","status":"active","location":"Chennai","contact_number":"1234567890"},"allocation":50},{"_id":"5c80c7240c253823fc44333f","start":"2018-12-31T18:30:00.000Z","end":"2019-10-09T18:30:00.000Z","employee":{"_id":"5c80c26e0c253823fc44332e","status":"active","location":"Chennai","contact_number":"1234567890"},"allocation":25}]


let res = _(works)
            .groupBy('employee._id')
            .map(g => ({...g[0].employee, work: _.map(g, ({employee, ...rest}) => ({...rest}))}))
            .value();
            
console.log(res)
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

推荐阅读