JavaScript - Replace an Item from JS Array

These are the following ways to replace an item from the JS array:

1. Using Array Indexing

The Array Indexing approach replaces an item in an array by directly accessing its position using the index and assigning a new value. This method is straightforward, modifies the original array, and is ideal for known index positions.

let arr = [1, 2, 3, 4, 5];
const idx = 2;
const val = 10;
arr[idx] = val;
console.log(arr);

[ 1, 2, 10, 4, 5 ]

2. Using the splice() Method

The splice() method in JavaScript is another way to replace items in an array. This method allows you to remove items and insert new ones at the specified position in the array.

Note: Splice() method deletes zero or more elements of an array starting with including the start_index element and replaces those elements with zero or more elements specified in the argument list.

let arr = [10, 20, 30];
arr.splice(1, 1, 25);  
console.log(arr);  

[ 10, 25, 30 ]

3. Using the indexOf() Method

Using the indexOf() method finds the index of an element in an array, allowing you to perform operations based on its presence or absence.

const arr = ['a', 'b', 'c'];
const idx = arr.indexOf('a');
if (idx !== -1) {
    arr[idx] = 'z';
}
console.log(arr);

[ 'z', 'b', 'c' ]

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Article Tags :

• JavaScript
• Web Technologies
• javascript-array
• JavaScript-DSA