JavaScript - How to Remove an Element from an Array?

Removing elements from an array is a fundamental operation in JavaScript, essential for data manipulation, filtering, and transformation. This guide will explore different methods to efficiently remove elements from an array, enhancing your understanding and capability in handling arrays.

1. Using pop() method

Thepop() method is used to remove the last element of the array and returns the removed element. This function decreases the length of the array by 1. 

// JavaScript code to illustrate pop() function
// to remove array elements

let arr = ["shift", "splice", "filter", "pop"];

// Popping the last element from the array
let popped = arr.pop();
console.log("Removed element: " + popped);
console.log("Remaining elements: " + arr);

Removed element: pop
Remaining elements: shift,splice,filter

2. Using shift() Method

The shift() method is used to remove the first element of the array and reduce the size of the original array by 1. 

// JavaScript code to illustrate shift() method
// to remove elements from array
let arr = ["shift", "splice", "filter", "pop"];

// Removing the first element from array
let shifted = arr.shift();
console.log("Removed element: " + shifted);
console.log("Remaining elements: " + arr);

Removed element: shift
Remaining elements: splice,filter,pop

3. Using splice() Method

The JavaScript Array splice() method can be used to remove any particular element from an array in JavaScript. Moreover, this function can be used to add/remove more than one element from an array. 

Syntax

array.splice(index, howmany, item1, ....., itemX)

let Arr = ["C++ ", " Java ", " Python ", " Go ", " Prolog"];

Arr.splice(2, 1);
console.log(Arr);

[ 'C++ ', ' Java ', ' Go ', ' Prolog' ]

4. Using filter() Method

This method is used to create a new array from a given array consisting of only those elements from the given array which satisfy a condition set by the argument function. 

// JavaScript to illustrate filter() method
function isPositive(value) {
    return value > 0;
}

let filtered = [101, 98, 12, -1, 848].filter(isPositive);
console.log("Positive elements in array: " + filtered);

Positive elements in array: 101,98,12,848

5. Using Delete Operator

Use the Delete Operator to remove elements from a JavaScript array. 

// Declare and initialize an array
let array = ["lodash", "remove", "delete", "reset"]

// Delete element at index 2
let deleted = delete array[2];

console.log("Removed: " + deleted);
console.log("Remaining elements: " + array);

Removed: true
Remaining elements: lodash,remove,,reset

6. Using _.remove() Method

The _.remove() method is used to remove all elements from the array that predicate returns True and returns the removed elements.

let _ = require("lodash");
let array = [101, 98, 12, -1, 848];
let evens = _.remove(array, function (n) {
    return n % 2 == 0;
});

console.log("odd elements: " + array);
console.log("even elements: " + evens);

Output: 

odd elements: 101, -1
even elements: 98, 12, 848

7. Using Array.prototype.slice() Method

The slice() method can be used to create a new array that excludes the elements you want to remove. Unlike splice(), which modifies the original array, slice() does not alter the original array but returns a new one.

Syntax

array.slice(start, end);

function removeElementAtIndex(arr, index) {
    return arr.slice(0, index).concat(arr.slice(index + 1));
}

const array = [1, 2, 3, 4, 5];
const indexToRemove = 2;

const newArray = removeElementAtIndex(array, indexToRemove);
console.log(newArray); 

[ 1, 2, 4, 5 ]