Javascript : sorting an object by child object given key value

Question

How to sort an object by a given value of its child keys ?

For instance, this object:

{
    "a": {
        "name": "Edward",
        "value": 21
    },
    "b": {
        "name": "Sharpe",
        "value": 37
    },
    "c": {
        "name": "And",
        "value": 45
    },
    "d": {
        "name": "The",
        "value": -12
    },
    "e": {
        "name": "Magnetic",
        "value": 13
    },
    "f": {
        "name": "Zeros",
        "value": 37
    }
}

would become sorted by the "value" key of its child objects:

{
    "d": {
        "name": "The",
        "value": -12
    },
    "e": {
        "name": "Magnetic",
        "value": 13
    },
    "a": {
        "name": "Edward",
        "value": 21
    },
    "b": {
        "name": "Sharpe",
        "value": 37
    },
    "f": {
        "name": "Zeros",
        "value": 37
    },
    "c": {
        "name": "And",
        "value": 45
    }
}

You can't really sort an objects properties - more reading here https://stackoverflow.com/questions/1069666/sorting-object-property-by-values you'd be better converting to an array of objects, and then sorting them — andy mccullough, Aug 11 '21 at 09:49
Sorry for the flag I misunderstood your question. But where is the point to order properties of an object? There is no use and is not possible... — PRSHL, Aug 11 '21 at 09:51
I take it, @DevonDahon you haven't tried at all - answer given, with caveat — Bravo, Aug 11 '21 at 09:53
@Bravo What I actually tried (and which works as well) is to add the key of each child object to itself, then convert the parent object to a `foo` array, sort it with `foo.sort((a, b) => a.value - b.value)` and recreate the object. — DevonDahon, Aug 11 '21 at 10:14
yeah, don't know what you mean - anyway, answer posted, don't rely on it — Bravo, Aug 11 '21 at 10:17
Does this answer your question? [Sorting an array of objects by property values](https://stackoverflow.com/questions/979256/sorting-an-array-of-objects-by-property-values) — Mickael B., Aug 11 '21 at 11:39
Thanks @MickaelB. but the post you mentioned concerns an array, not an object — DevonDahon, Aug 11 '21 at 15:17

Bravo · Accepted Answer · 2021-08-11T09:57:26.090

This works

var obj = {
    "a": {
        "name": "Edward",
        "value": 21
    },
    "b": {
        "name": "Sharpe",
        "value": 37
    },
    "c": {
        "name": "And",
        "value": 45
    },
    "d": {
        "name": "The",
        "value": -12
    },
    "e": {
        "name": "Magnetic",
        "value": 13
    },
    "f": {
        "name": "Zeros",
        "value": 37
    }
};

const result = Object.fromEntries(Object.entries(obj).sort(([,{value:a}],[,{value:b}])=>a-b));
console.log(result);
console.log(Object.keys(result).join());

but while this seems to work, object property order is not strictly defined, so whose to say it will always work

for example, if some of the top level keys are numeric, this is the result

var obj = {
    "a": {
        "name": "Edward",
        "value": 21
    },
    "b": {
        "name": "Sharpe",
        "value": 37
    },
    "1": {
        "name": "And",
        "value": 45
    },
    "d": {
        "name": "The",
        "value": -12
    },
    "2": {
        "name": "Magnetic",
        "value": 13
    },
    "f": {
        "name": "Zeros",
        "value": 37
    }
};

const result = Object.fromEntries(Object.entries(obj).sort(([,{value:a}],[,{value:b}])=>a-b));
console.log(result);
console.log(Object.keys(result).join()); // want d2abf1 - get 12dabf

this is because numeric keys ALWAYS precede non-numeric, regardless of creation order - thats one thing that IS defined about object property order

Javascript : sorting an object by child object given key value

1 Answers1