how to group by nested properties using lodash?

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I have array of objects

{
    "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
        }
    ]
}

I need to convert them into

[{
    "_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
    }]
}]

I have done it by partially using lodash and vanilla js and it works completely fine. but readability wise is completely bad. I want to achieve this using just lodash alone. Any help?

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);

You can do it succinctly using plain JavaScript with Object.values(), Array.reduce() and desctructuring assignment:

const data = {"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}]};

const result = Object.values(data.work.reduce((acc, work) => {
  const { employee: { _id, ...rest }, ...job } = work;
  const jobs = (acc[_id] || {}).work || [];
  acc[_id] = { _id, ...rest, work: [...jobs, job] };
  return acc;
}, {}));

console.log(result);

Nested grouping of arrays � GitHub, Nesting allows elements in an array to be grouped into a hierarchical tree _ = require('lodash'); var nest = function (seq, keys) { if (!keys.length) return seq; var� How to sort array of objects with deep nested properties using lodash orderBy? Ask Question Asked today. An alien group attacks earth but fails, what level of

Hopefully, this is what you are looking for.

  1. First group it by employee_.id
  2. Then map each group, take employee of first one (since every group must have one entry)
  3. Then map all other members (and take outer part) of each group to work (everything apart from employee object)

Here is the example below:

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>

uniq(array, Creates an array of elements split into groups the length of size . Creates a slice of array with n elements dropped from the beginning. If an object is provided for predicate the created _.matches style callback returns true for elements that� TL;DR Lodash has a helper for drilling down into nested objects and arrays, but only using keys and indexes, not properties of items in arrays. You'd need to make your own function for this. You'd need to make your own function for this.

You can create a function that uses lodash's _.flow() that groups by the employee id, and then creates an employee object with work array:

const { flow, partialRight: pr, groupBy, map, head, get, omit } = _

const fn = flow(
  pr(groupBy, 'employee._id'),
  pr(map, group => ({ // create the employee objects
    ...get(head(group), 'employee'), // get the employee data and spread it
    work: group.map(o => omit(o, 'employee')) // create the work array by removing the employee from each work object
  }))
)

const data = {"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}]}

const result = fn(data.work)

console.log(result)
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js"></script>

Nested grouping of arrays, Nesting allows elements in an array to be grouped into a hierarchical _ = require('lodash'); var nest = function (seq, keys) { if (!keys.length)� lodash. fix the nested objects (the order of base and object was mixed Using lodash nested array of object will be sorted out I have the below dataset which needs to be sorted based on "AcctCode" and "SuperID" as below expected result using lodash. has() to easily check for nested property existence I like the post because I'm not a lodash user

Lodash Group By - JSFiddle, Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle code editor. http://stackoverflow.com/questions/24627026/lo-dash-array-grouping. 3. -->. This will group your results by last name. However in your case you need to group by multiple properties - you can use this snippet to enchant this function. Of course you can use this code multiple times. Lodash allows you to install its modules one-by-one (npm i lodash.groupby);

Deep pick using lodash/underscore, pickDeep would perform a deep clone of the object and would "pick" up all nested objects containing the given keys. All containers containing the nested objects� Lodash makes JavaScript easier by taking the hassle out of working with arrays, numbers, objects, strings, etc. Lodash’s modular methods are great for: Iterating arrays, objects, & strings; Manipulating & testing values; Creating composite functions. Module Formats. Lodash is available in a variety of builds & module formats. lodash & per

Iterating Over and Reducing Data, To help with this issue of brittle transformations, lodash provides the clone function. This function takes an object and returns a copy of that object. That copy is now� It does not use lodash. It's gotten complex enough that it probably should break into smaller pieces, and lodash might help with that. It includes not just gc , but also time from the original records, and will, in fact, include anything else from there.

Comments
  • Thanks for it +1 Neat and Clean, But I am looking for lodash answers, anyway I will accept your answer, If I could not find anything with lodash.
  • @Thamaraiselvam didn't understand why you accepted the loadash version of answers (mine & Ori Drori's ans) and then unaccepted. this answer with plain JS looks good, and then you asked for lodash versoin (in the last comment of this ans), after that I came up with some lodash solution (thinking that may help you). Don'w know what exactly you were looking for.
  • @KoushikChatterjee you really did a great job posting best answer. since I am using typescript , there are some syntax issues with your answers and I was in hurry so I have used jo_va answer.
  • @Thamaraiselvam Hmm, actually it's not about my answer or anyone's answer, if you have any trouble, comment regarding any answer you should comment there, in order to have a bigger picture, for all SO users who might face this kind of problem.
  • Perfect +1 , Thanks for it
  • @OriDrori Try avoiding omit, rather take rest of the attributes as {employee, ...rest} and use rest