What does toSorted() do?

JavaScriptJunior~1 min read

toSorted() is a new, non-mutating counterpart to the sort() method in JavaScript, added in the ECMAScript 2023 (ES14) standard.

It lets you sort an array, but does not change the original array - it returns a new sorted copy.

Syntax:

javascript

const newArray = array.toSorted(compareFn);

Parameter	Description
`compareFn`	(optional) comparison function, same as `sort()` - `(a, b) => a - b`

Example:

javascript

const numbers = [3, 1, 4, 2];
const sorted = numbers.toSorted((a, b) => a - b);

console.log(sorted); // [1, 2, 3, 4]
console.log(numbers); // [3, 1, 4, 2] - the original array did not change

Unlike sort(), which mutates the original, toSorted() returns a new array with the elements sorted.

Comparison with `sort()`

Method	Changes the original array	Returns	Safe
`sort()`	Yes	The same array	No
`toSorted()`	No	A new array	Yes

Comparison example:

javascript

const arr = [5, 2, 9];

const sorted1 = arr.sort();      // mutates
const sorted2 = arr.toSorted();  // does not mutate

console.log(arr);     // [2, 5, 9] - mutated!
console.log(sorted1); // [2, 5, 9]
console.log(sorted2); // [2, 5, 9] - a new independent array

Sorting numbers:

javascript

const nums = [10, 2, 5, 1];
const asc = nums.toSorted((a, b) => a - b);
const desc = nums.toSorted((a, b) => b - a);

console.log(asc);  // [1, 2, 5, 10]
console.log(desc); // [10, 5, 2, 1]
console.log(nums); // [10, 2, 5, 1] - unchanged

When to use it

When it matters to preserve the original data (for example, in React, Redux, functional code).
When you need to sort data safely, without side effects.

New method	Old counterpart	What it does	Mutates?
`toReversed()`	`reverse()`	Reverses the order	No
`toSorted()`	`sort()`	Sorts	No
`toSpliced()`	`splice()`	Removes / inserts elements	No
`with()`	`arr[index] = value`	Replaces an element by index	No

Summary:

What it does	Creates a sorted copy of the array
Changes the original array	No
Returns	A new array
Supports a comparison function	Yes
Example	`[3,1,2].toSorted((a,b)=>a-b)` -> `[1,2,3]`

In short: toSorted() is a safe, non-mutating alternative to sort(), which returns a new sorted array, keeping the original unchanged.

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