javascript - Sort array of objects by nested property with lodash - Stack Overflow

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I have an array of objects like this

[{ ‘a’: { id: 4 }}, { ‘b’: { id: 3 }}, { ‘c’: { id: 2 }}, { ‘d’: { id: 5 }}]

I want to know with lodash the sorting of the objects according to the id. I would expect to receive something like [‘d’, ‘a’, ‘b’, ‘c’].

I tried to search this but I didn’t find an answer which works with different keys in each object. I tried to do this with lodash’ different functions (many). So I thought there may be a good and maybe short way to solve this.

I have an array of objects like this

[{ ‘a’: { id: 4 }}, { ‘b’: { id: 3 }}, { ‘c’: { id: 2 }}, { ‘d’: { id: 5 }}]

I want to know with lodash the sorting of the objects according to the id. I would expect to receive something like [‘d’, ‘a’, ‘b’, ‘c’].

I tried to search this but I didn’t find an answer which works with different keys in each object. I tried to do this with lodash’ different functions (many). So I thought there may be a good and maybe short way to solve this.

• javascript
• lodash

Share Follow asked Feb 24, 2019 at 15:00 Pichi WuanaPichi Wuana 75222 gold badges1010 silver badges3737 bronze badges 1

• In the first step, transform your array to [{key: 'a', id: 4}, {key: 'b', id: 3}, …]. – Bergi Commented Feb 24, 2019 at 15:03

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5 Answers 5

Sorted by: Reset to default 5

Here is a plain JavaScript solution.

Since you want to get the sorted keys as the result, this solution does not modify the original array, thanks to the first map before sort:

const data = [{ 'a': { id: 4 }}, { 'b': { id: 3 }}, { 'c': { id: 2 }}, { 'd': { id: 5 }}];

const sorted = data
  .map(x => Object.entries(x)[0])
  .sort((a, b) => b[1].id - a[1].id)
  .map(x => x[0]);
  
console.log(sorted);

If you don't care about mutating the original array, you can directly sort using Object.values() and then return the first key with Object.keys():

const data = [{ 'a': { id: 4 }}, { 'b': { id: 3 }}, { 'c': { id: 2 }}, { 'd': { id: 5 }}];

const sorted = data
  .sort((a, b) => Object.values(b)[0].id - Object.values(a)[0].id)
  .map(x => Object.keys(x)[0]);
  
console.log(sorted);

You can simply do it with javascript by using sort method and mapping over the returned array and returning the keys

var data = [{ 'a': { id: 4 }}, { 'b': { id: 3 }}, { 'c': { id: 2 }}, { 'd': { id: 5 }}]

const res = data.sort((a, b)  => Object.values(b)[0].id - Object.values(a)[0].id).map(obj => Object.keys(obj)[0]);

console.log(res);

Or you can use lodash with orderBy and map methods

    var data = [{ 'a': { id: 4 }}, { 'b': { id: 3 }}, { 'c': { id: 2 }}, { 'd': { id: 5 }}]

    const res = _.orderBy(data, function(a) {
      return Object.values(a)[0].id
    }, ['desc']).map(o => Object.keys(o)[0])
    
    console.log(res);

<script src="https://cdnjs.cloudflare./ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

You can first sort based on id and than map the key.

let obj = [{ 'a': { id: 4 }}, { 'b': { id: 3 }}, { 'c': { id: 2 }}, { 'd': { id: 5 }}]

let op = obj
        .sort((a,b) => Object.values(b)[0].id - Object.values(a)[0].id)
        .map(e => Object.keys(e)[0])

console.log(op)

This is a lodash/fp version of jo_va's solution.

Use _.flow() to create a function that maps each object to a [key, { id }] pair. Sort with _.orderBy() according to id. Iterate with _.map() and dxtract the _.head() (the key):

const { flow, flatMap, toPairs, orderBy, map, head } = _

const fn = flow(
  flatMap(toPairs), // convert each object to pair of [key, { id }]
  orderBy(['[1].id'], ['desc']), // order descending by the id
  map(head) // extract the original key
)

const data = [{ 'a': { id: 4 }}, { 'b': { id: 3 }}, { 'c': { id: 2 }}, { 'd': { id: 5 }}]

const result = fn(data)

console.log(result)

<script src='https://cdn.jsdelivr/g/lodash@4(lodash.min.js+lodash.fp.min.js)'></script>

const data = [{ a: { id: 4 }}, { b: { id: 3 }}, { c: { id: 2 }}, { d: { id: 5 }}];
data.sort((a, b) => Object.values(b)[0].id - Object.values(a)[0].id);
console.log(data);

The above snippet shows how to do it with Array.sort. Lodash should work similarly.

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