Array.prototype.toSorted()

The toSorted() method of Array instances is the copying version of the sort() method. It returns a new array with the elements sorted in ascending order.

Syntax

js
toSorted()
toSorted(compareFn)

Parameters

compareFn Optional

Specifies a function that defines the sort order. If omitted, the array elements are converted to strings, then sorted according to each character's Unicode code point value.

a

The first element for comparison.

b

The second element for comparison.

Return value

A new array with the elements sorted in ascending order.

Description

See sort() for more information on the compareFn parameter.

When used on sparse arrays, the toSorted() method iterates empty slots as if they have the value undefined.

The toSorted() method is generic. It only expects the this value to have a length property and integer-keyed properties.

Examples

Sorting an array

js
const months = ["Mar", "Jan", "Feb", "Dec"];
const sortedMonths = months.toSorted();
console.log(sortedMonths); // ['Dec', 'Feb', 'Jan', 'Mar']
console.log(months); // ['Mar', 'Jan', 'Feb', 'Dec']

const values = [1, 10, 21, 2];
const sortedValues = values.toSorted((a, b) => a - b);
console.log(sortedValues); // [1, 2, 10, 21]
console.log(values); // [1, 10, 21, 2]

For more usage examples, see sort().

Using toSorted() on sparse arrays

Empty slots are sorted as if they have the value undefined. They are always sorted to the end of the array and compareFn is not called for them.

js
console.log(["a", "c", , "b"].toSorted()); // ['a', 'b', 'c', undefined]
console.log([, undefined, "a", "b"].toSorted()); // ["a", "b", undefined, undefined]

Calling toSorted() on non-array objects

The toSorted() method reads the length property of this. It then collects all existing integer-keyed properties in the range of 0 to length - 1, sorts them, and writes them into a new array.

js
const arrayLike = {
  length: 3,
  unrelated: "foo",
  0: 5,
  2: 4,
  3: 3, // ignored by toSorted() since length is 3
};
console.log(Array.prototype.toSorted.call(arrayLike));
// [4, 5, undefined]

Specifications

Specification
ECMAScript Language Specification
# sec-array.prototype.tosorted

Browser compatibility

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See also