Sorting object in JS by one of the keys in each element

Question

I have an object in JS structured as follows:

[{
    "x": 2.31,
    "y": 0.538
}, 
{
    "x": 7.07,
    "y": 0.469
}, 
{
    "x": 6.02,
    "y": 0.469
}, 
{
    "x": 2.18,
    "y": 0.458
}]

I need to sort by one of the keys in each element (sort by x). The result would look like this:

[{
    "x": 2.18,
    "y": 0.458
}, 
{
    "x": 2.31,
    "y": 0.538
}, 
{
    "x": 6.02,
    "y": 0.469
}, 
{
    "x": 7.07,
    "y": 0.469
}]

The following approach doesn't work with the above structure:

var sorted = [];
for(var key in dict) {
    sorted[sorted.length] = key;
}
sorted.sort();

Nor does the following:

function sortObject(o) {
    return Object.keys(o).sort().reduce((r, k) => (r[k] = o[k], r), {});
}

Possible duplicate of [Sort array of objects by string property value in JavaScript](https://stackoverflow.com/questions/1129216/sort-array-of-objects-by-string-property-value-in-javascript) — t.niese, Jan 22 '18 at 05:38
Or this one: [Sorting an array of JavaScript objects](https://stackoverflow.com/questions/979256/sorting-an-array-of-javascript-objects) — t.niese, Jan 22 '18 at 05:41
That was it...apologies. Your first link. Didn't see it in my search. Thank you. — Cybernetic, Jan 22 '18 at 05:44

score 1 · Accepted Answer · answered Jan 22 '18 at 05:49

1

Implement a custom sort method.

var arr = [{ "x": 2.31, "y": 0.538 }, { "x": 7.07, "y": 0.469 }, { "x": 6.02, "y": 0.469 }, { "x": 2.18, "y": 0.458 }]
arr.sort((a,b) => a.x - b.x)
console.log(arr);

answered Jan 22 '18 at 05:49

Hassan Imam

21,956
5
41
51

Nabin Paudyal · Answer 2 · 2018-01-22T05:52:51.227

0

What you have do here is implement a custom sort method for comparison between the elements in your array.

Try this out.

const array = [{
    "x": 2.31,
    "y": 0.538
}, 
{
    "x": 7.07,
    "y": 0.469
}, 
{
    "x": 6.02,
    "y": 0.469
}, 
{
    "x": 2.18,
    "y": 0.458
}];

array.sort((obj1, obj2) => {
   return obj1.x - obj2.x;
});

edited Jan 22 '18 at 05:52

answered Jan 22 '18 at 05:45

Nabin Paudyal

1,591
8
14

score 0 · Answer 3 · answered Jan 22 '18 at 05:47

0

Yes, you can sort the key value of the object by comparing the key's value using parseFloat.

var coordinates=[{
    "x": 2.31,
    "y": 0.538
}, 
{
    "x": 7.07,
    "y": 0.469
}, 
{
    "x": 6.02,
    "y": 0.469
}, 
{
    "x": 2.18,
    "y": 0.458
}]

var sortedKey=coordinates.sort(function(a, b) {
    return parseFloat(a.x) - parseFloat(b.x);
});
console.log(sortedKey);

answered Jan 22 '18 at 05:47

CodeZombie

2,027
3
16
30

The values are already numbers sow by should it be relevant for this example to use `parseFloat`? – t.niese Jan 22 '18 at 05:56

score 0 · Answer 4 · answered Jan 22 '18 at 05:48

You can use lodash. https://lodash.com/docs/4.17.4#sortBy

lodash is a modern JavaScript utility library delivering modularity, performance & extras.

Demo: http://jsfiddle.net/e2ccmbhh

let arr = [{
  "x": 2.31,
  "y": 0.538
}, 
{
  "x": 7.07,
  "y": 0.469
}, 
{
  "x": 6.02,
  "y": 0.469
}, 
{
  "x": 2.18,
  "y": 0.458
}]

let sortedArr = _.sortBy(arr, 'x');

score 0 · Answer 5 · answered Jan 22 '18 at 05:51

You can use Javascript builtin sort() method to do that.

var myList = [{
            "x": 2.31,
            "y": 0.538
        },
        {
            "x": 7.07,
            "y": 0.469
        },
        {
            "x": 6.02,
            "y": 0.469
        },
        {
            "x": 2.18,
            "y": 0.458
        }];

    var sortedList = myList.sort(function(a, b){
        return a.x - b.x;
    });

    console.log(sortedList);

Sorting object in JS by one of the keys in each element

5 Answers5