Array.prototype.toSorted()

toSorted(compareFn)

Returns: array · Added in vES2023 · Updated March 13, 2026 · Array Methods

array sort immutable

The toSorted() method returns a new array with the elements sorted. It’s the immutable counterpart to sort() — your original array stays untouched, which is essential for React, Redux, and other scenarios where immutability matters.

Syntax

arr.toSorted(compareFn)

Parameters

Parameter	Type	Description
`compareFn`	function	Optional function that defines sort order

The compare function receives two arguments:

a: First element for comparison
b: Second element for comparison

Return negative if a < b, positive if a > b, zero if equal.

Examples

Basic usage (numbers)

const arr = [3, 1, 2];
const sorted = arr.toSorted();
console.log(arr);    // [3, 1, 2] (unchanged)
console.log(sorted); // [1, 2, 3]

Descending order

const nums = [5, 2, 8, 1, 9];
const descending = nums.toSorted((a, b) => b - a);
console.log(descending); // [9, 8, 5, 2, 1]

Sorting strings

const words = ['banana', 'apple', 'cherry', 'date'];
const alphabetical = words.toSorted();
console.log(alphabetical); // ['apple', 'banana', 'cherry', 'date']

// Case-insensitive sorting
const mixed = ['Apple', 'banana', 'Cherry', 'date'];
const caseInsensitive = mixed.toSorted((a, b) => 
  a.localeCompare(b)
);
console.log(caseInsensitive); // ['Apple', 'banana', 'Cherry', 'date']

Sorting objects by property

const users = [
  { name: 'Alice', age: 30 },
  { name: 'Bob', age: 25 },
  { name: 'Carol', age: 35 }
];

const byAge = users.toSorted((a, b) => a.age - b.age);
console.log(byAge.map(u => u.name)); // ['Bob', 'Alice', 'Carol']

const byName = users.toSorted((a, b) => a.name.localeCompare(b.name));
console.log(byName.map(u => u.name)); // ['Alice', 'Bob', 'Carol']

Chaining with other methods

const data = [4, 2, 5, 1, 3];

const result = data
  .filter(n => n > 2)
  .toSorted()
  .map(n => n * 2);

console.log(result); // [6, 8, 10]

Sorting with nulls and undefined

const mixed = [3, null, 1, undefined, 2];

// Put nulls/undefined at the end
const sorted = mixed.toSorted((a, b) => {
  if (a == null) return 1;
  if (b == null) return -1;
  return a - b;
});
console.log(sorted); // [1, 2, 3, null, undefined]

Common Mistakes

The default sort converts elements to strings:

[10, 2, 21].sort();        // [10, 2, 21] - wrong!
[10, 2, 21].toSorted();   // [10, 2, 21] - still wrong without compareFn!
[10, 2, 21].toSorted((a, b) => a - b); // [2, 10, 21] - correct