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How can you access the first and last elements of a JavaScript array?
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- The first element is accessed using arr[0] or arr.at(0). 2. The last element is accessed using arr[arr.length - 1] or arr.at(-1), with .at(-1) being more readable in modern JavaScript, and both return undefined for empty arrays.
You can access the first and last elements of a JavaScript array using simple indexing and built-in properties. Here's how:
1. Accessing the First Element
The first element of an array is always at index 0. You can access it directly using bracket notation:
const arr = ['apple', 'banana', 'cherry']; const first = arr[0]; console.log(first); // 'apple'
?? If the array is empty,
arr[0]will returnundefined.
2. Accessing the Last Element
Since array lengths can vary, the last element is at index arr.length - 1. Use this formula to get it:
const arr = ['apple', 'banana', 'cherry']; const last = arr[arr.length - 1]; console.log(last); // 'cherry'
? This works reliably as long as the array has at least one element. For empty arrays, it returns
undefined.
Alternative Methods (Modern JavaScript)
Using .at() method (ES2022 )
The .at() method allows relative indexing. Use at(-1) for the last element:
const arr = ['apple', 'banana', 'cherry']; console.log(arr.at(0)); // 'apple' — first console.log(arr.at(-1)); // 'cherry' — last
This is cleaner and more readable, especially for the last element.
Using destructuring and rest (for the first)
You can extract the first element via destructuring:
const [first] = ['apple', 'banana', 'cherry']; console.log(first); // 'apple'
And for the last, it's less practical but possible with reverse or length tricks — not recommended for this purpose.
Summary
-
First element:
arr[0]orarr.at(0) -
Last element:
arr[arr.length - 1]orarr.at(-1)
Use .at(-1) if you're targeting modern environments — it's more expressive and avoids the length - 1 math.
Basically, it's straightforward — just remember the index rules and watch out for empty arrays.
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