JavaScript Array splice() Method

Q: How do you use the splice() method?

The splice() method is used with the following syntax:array.splice(start, deleteCount, item1, item2, ...);

Last Updated : 05 Sep, 2024

JavaScript Array splice() Method is an inbuilt method in JavaScript that is used to change the contents of an array by removing or replacing existing elements and/or adding new elements. It modifies the original array and returns an array of the removed elements.

Syntax

Array.splice( index, remove_count, item_list )

Parameters:

index: It is a required parameter. This parameter is the index from which the modification of the array starts (with the origin at 0). This can be negative also, which begins after many elements counting from the end.
remove_count: The number of elements to be removed from the starting index.
items_list: The list of new items separated by a comma operator that is to be inserted from the starting index.

Return Value:

While it mutates the original array in place, still it returns the list of removed items. In case there is no removed array it returns an empty array.

Example 1: Basic Usage of splice() Method

In this example, JS is replaced with “PHP” and React_Native, and React is inserted at the second-to-last index.

JavaScript

let webDvlop = ["HTML", "CSS", "JS", "Bootstrap"];

console.log(webDvlop);

// Add 'React_Native' and 'Php' after removing 'JS'.
let removed = webDvlop.splice(2, 1, 'PHP', 'React_Native')

console.log(webDvlop);
console.log(removed);

// No Removing only Insertion from 2nd 
// index from the ending
webDvlop.splice(-2, 0, 'React')
console.log(webDvlop)

Output

[ 'HTML', 'CSS', 'JS', 'Bootstrap' ]
[ 'HTML', 'CSS', 'PHP', 'React_Native', 'Bootstrap' ]
[ 'JS' ]
[ 'HTML', 'CSS', 'PHP', 'React', 'React_Native', 'Bootstrap' ]

Example 2: Manipulating an Array with splice() Method

In this example we demonstrates modifying the languages array. It first replaces ‘Html’ with ‘Julia’ and ‘Php,’ then inserts ‘Pascal’ before the second-to-last element, logging the changes throughout.

JavaScript

let languages = ['C++', 'Java', 'Html', 'Python', 'C'];

console.log(languages);

// Replace 'Html' with 'Julia' and 'Php'.
let removed = languages.splice(2, 1, 'Julia', 'Php');

console.log(languages);
console.log(removed);

// Insert 'Pascal' before the second-to-last element.
languages.splice(-2, 0, 'Pascal');
console.log(languages);

Output

[ 'C++', 'Java', 'Html', 'Python', 'C' ]
[ 'C++', 'Java', 'Julia', 'Php', 'Python', 'C' ]
[ 'Html' ]
[
  'C++',    'Java',
  'Julia',  'Php',
  'Pascal', 'Python',
  'C'
]

We have a complete list of Javascript Array methods, to check those please go through this Javascript Array Complete reference article.

Supported Browsers:

JavaScript Array splice() Method- FAQs

How do you use the splice() method?

The splice() method is used with the following syntax:

array.splice(start, deleteCount, item1, item2, …);

Can you use splice() to only add elements to an array without removing any?

Yes, by omitting the items to add, you can remove elements without adding any.

What happens if the start index is negative?

If the start index is greater than the array length, splice() will start adding the new elements at the end of the array without removing any elements.