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.
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.com/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.net/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.
[{key: 'a', id: 4}, {key: 'b', id: 3}, …].