How to Sort JavaScript Objects by Key

By default, keys in a JavaScript object are unordered.

This means that the order of the keys in the object is not guaranteed.

You can, however, sort these keys to form a new object.

In this post, we'll learn how to sort a JavaScript object by key.

How to sort a JavaScript object by key

To start, let's create a JavaScript object with some keys and values.

JAVA
const object = {
    "name": "John",
    "age": 30,
    "city": "New York"
};

console.log(object);

BASH
{
    "name": "John",
    "age": 30,
    "city": "New York"
}

We can use a combination of built-in functions to take this object, iterate over the keys, sort them, then build up a new object using these ordered keys.

More specifically, we can use Object.keys() to get the keys in an array, sort() to sort them, then use reduce() to iterate through each one and set the key and value to a new object.

JAVASCRIPT
const object = {
    "name": "John",
    "age": 30,
    "city": "New York"
};

const sortObject = object => {
    return Object.keys(object).sort().reduce((acc, key) => {
        acc[key] = object[key];
        return acc;
    }, {});
};

const sortedObject = sortObject(object);

console.log(sortedObject);

BASH
{
    "age": 30,
    "city": "New York",
    "name": "John"
}

Notice how now the keys are in the order we want them to be, sorted alphabetically.

If you want this code more compactly, this can be accomplished in one line:

JAVASCRIPT
const object = {
    "name": "John",
    "age": 30,
    "city": "New York"
};

const sortObject = object => Object.keys(object).sort().reduce((acc, key) => (acc[key] = object[key], acc), {});

const sortedObject = sortObject(object);

console.log(sortedObject);

BASH
{
    "age": 30,
    "city": "New York",
    "name": "John"
}

Conclusion

In this post, we learned how to sort a JavaScript object by key.

Simply use a combination of built-in functions to get the keys from your object, iterate through them one by one to sort them, then use reduce() to create a new object from it.

Thanks for reading!

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