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Delete from a JS Array

Last Updated : 21 Nov, 2024

The following are different delete operations on a JS Array:

This operation removes the first element of an array, shifting all other elements to lower indices. The array's length is reduced by one. Methods like shift() can be used for this, which directly mutates the array.

let a = [10, 20, 30, 40];
let res = a.shift();
console.log(res); 

You can delete the first element of an array using many other methods. Refer to this article for more methods.

To remove an element from a specific index, you can use a method that targets that index. This operation deletes one or more elements starting at the specified index while shifting subsequent elements to fill the gap. The most commonly used method for this is splice().

let a = [10, 20, 30, 40];
let idx = 2;
let res = a.splice(idx, 1);
console.log(res); 

You can delete an element from a specific index using many other methods. Refer to this article for more methods.

This operation removes the last element in the array, reducing its length by one. This is typically achieved using the pop() method, which mutates the original array and returns the removed element.

let a = [10, 20, 30, 40];
let res = a.pop();
console.log(res);

You can delete the last element of an array using many other methods. Refer to this article for more methods.

To delete the first occurrence of a specific value, the value is located within the array (e.g., using indexOf()), and then it is removed. This operation ensures that only the first matching element is deleted while leaving other instances of the value intact.

let a = [10, 20, 30, 20, 40];
let x = 20;
let idx = a.indexOf(x);
if (idx !== -1) {
  a.splice(idx, 1);
}
console.log(a);

[ 10, 30, 20, 40 ]

You can delete the first occurrence of a specific value using many other methods. Refer to this article for more methods.

This operation targets the last occurrence of a specific value in the array. Using methods like lastIndexOf() to locate the value ensures that only the last matching element is removed, leaving earlier instances unaffected.

let a = [10, 20, 30, 20, 40];
let x = 20;
let idx = a.lastIndexOf(x);
if (idx !== -1) {
  a.splice(idx, 1);
}
console.log(a);

[ 10, 20, 30, 40 ]

You can delete the last occurrence of a specific value using many other methods. Refer to this article for more methods.

Removes all instances of a specific value by filtering the array to exclude the unwanted value.

let a = [10, 20, 30, 20, 40];
let x = 20;
let res = a.filter(e => e !== x);
console.log(res); 

You can delete all instances of a specific value using many other methods. Refer to this article for more methods.

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