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Get the Last Element in an Array in JavaScript

 1 year ago
source link: https://masteringjs.io/tutorials/fundamentals/get-last-element-array
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Get the Last Element in an Array in JavaScript

Jan 6, 2023

To get the last element in an array, you get the array's .length property and get the element at index length - 1.

const array = ['a', 'b', 'c'];
array.length; // 5
array[array.length - 1]; // 5

JavaScript doesn't throw array out of bounds exceptions, so it is safe to use array[array.length - 1] without checking if array.length === 0. JavaScript will return undefined if array is empty.

const array = [];
array[array.length - 1]; // undefined

Using slice()

You can also use the slice() function to get the last element in an array. The slice() method returns a subsection of the array, and supports negative indexes. That means slice(-1) returns a 1 element array with just the last element in the original array.

const array = [1, 2, 3, 4, 5];
array.slice(-1); // [5]

So to get the last element of an array without referencing the length property using the following:

const lastElement = array.slice(-1)[0]; // 5

You can also use destructuring if you do not wish to use the syntax from above.

const array = [1, 2, 3, 4, 5];
const [last] = array.slice(-1); // returns 5

This approach also returns undefined if array is empty.

const array = [];
const [last] = array.slice(-1); // undefined

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