The JavaScript array.at() method

Q: How do I get the last element of an array?

Use arr.at(-1), which counts from the end — cleaner than arr[arr.length - 1].

Q: What is the difference between at() and bracket notation?

For positive indices they're the same. The difference is at() accepts negative indices to count from the end, which arr[-1] does not.

Q: Does at() work on strings?

Yes. "hello".at(-1) returns "o".

Q: What does at() return for an out-of-range index?

undefined, the same as bracket access.

Method JavaScript All modern browsers Updated June 23, 2026

Quick answer

The at() method returns the element at a given index, and crucially it accepts negative indices that count from the end. arr.at(-1) is the last element — far nicer than arr[arr.length - 1]. For positive indices it behaves just like bracket notation arr[i].

Overview

at() reads an element by index, with one big convenience over the usual square brackets: it understands negative indices. arr.at(-1) gives you the last element, arr.at(-2) the second-to-last, and so on. That replaces the clunky arr[arr.length - 1] with something readable.

For non-negative indices, at(2) does exactly what arr[2] does. The win is entirely at the back end of the array, where counting from the end is a common need — grabbing the last item of a list, the most recent entry, the final character (it works on strings too).

It returns undefined if the index is out of range, the same as bracket access. Use bracket notation for ordinary forward indexing and at() when you want to count from the end without the length arithmetic.

Syntax

array.at(index)

[10, 20, 30].at(0)   // 10
[10, 20, 30].at(-1)  // 30 (last)
[10, 20, 30].at(-2)  // 20

Parameters

The array.at() method accepts the following parameters.

Parameter	Description
`index`	The position to read. Negative values count back from the end (`-1` is the last element).

Example

Live example

<pre id="out" style="font:15px ui-monospace,monospace"></pre>
<script>
  const log = ['boot', 'login', 'click', 'logout'];

  document.getElementById('out').textContent =
    'first: ' + log.at(0) + '\n' +
    'last:  ' + log.at(-1) + '\n' +
    'prev:  ' + log.at(-2); // first: boot / last: logout / prev: click
</script>

Best practices

Use arr.at(-1) for the last element instead of arr[arr.length - 1].
Stick with bracket notation arr[i] for ordinary forward indexing.
It returns undefined for an out-of-range index, like bracket access.
It works on strings too — str.at(-1) is the last character.

Frequently asked questions

How do I get the last element of an array?

Use arr.at(-1), which counts from the end — cleaner than arr[arr.length - 1].

What is the difference between at() and bracket notation?

For positive indices they're the same. The difference is at() accepts negative indices to count from the end, which arr[-1] does not.

Does at() work on strings?

Yes. "hello".at(-1) returns "o".

What does at() return for an out-of-range index?

undefined, the same as bracket access.

array.concat()

References