What does toReversed() do?

JavaScriptMiddle~1 min read

The toReversed() method is a new, safe counterpart to the older reverse() method, added in the ECMAScript 2023 (ES14) standard.

What it does

toReversed() returns a new array in which the elements are in reverse order, while the original array is not changed.

Example:

javascript

const arr = [1, 2, 3];
const reversed = arr.toReversed();

console.log(reversed); // [3, 2, 1]
console.log(arr);      // [1, 2, 3] - the original stayed the same

Unlike reverse(), which mutates the array, toReversed() makes a clean (immutable) copy.

Comparison with `reverse()`

Method	Changes the original array	Returns
`reverse()`	Yes	The same array (mutated)
`toReversed()`	No	A new array (reversed)

Comparison example:

javascript

const a = [1, 2, 3];

const b = a.reverse();
console.log(a); // [3, 2, 1] - changed
console.log(b); // [3, 2, 1] - the same reference

const c = a.toReversed();
console.log(c); // [1, 2, 3] - a new array
console.log(a); // [3, 2, 1] - the original is untouched

When to use it

When you need to safely reverse an array without damaging the original.
Great for functional and reactive programming, where it's important not to mutate data (for example, in React or Redux).

Briefly:

What it does	Creates a reversed copy of the array
Changes the original array	No
Returns	A new array
Added in	ECMAScript 2023
Example	`[1, 2, 3].toReversed()` -> `[3, 2, 1]`

JavaScript added a whole family of safe counterparts.

New method	Old mutating counterpart	What it does
`toReversed()`	`reverse()`	Reverses the array
`toSorted()`	`sort()`	Sorts without changing the original
`toSpliced()`	`splice()`	Returns a modified copy
`with()`	direct assignment by index	Returns a copy with a replaced element

Summary: toReversed() is a non-mutating way to reverse an array, introduced in newer versions of JavaScript (ES2023).

Safe, clean, predictable. Does not change the original array.

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What does toReversed() do?

#What it does

#Example:

#Comparison with reverse()

#Comparison example:

#When to use it

#Briefly:

#Related non-mutating methods (ES2023+):