JavaScript Program to Remove All Occurrences of an Element in an Array
We are given an array and a particular number. We need to check for the existence of the element in the array. If the element is not present in the array we will return -1. Otherwise, we will remove all the occurrences of the given element from the array.
Table of Content
- Using filter() method
- Using splice() method
- Using forEach() method
Using filter() method
The filter() method creates a new array with all elements that passed the test implemented by the given callback function.
Example: The below code removes all occurrences of an element from an Array using the filter() method in JavaScript.
function removeElement(arr, elem) {
if(!arr.includes(elem)){
return -1;
}
return arr.filter(
(item) => item !== elem);
}
const array =
[1, 2, 3, 4, 2, 5, 2];
const result1 =
removeElement(array, 2);
const result2 =
removeElement(array, 6);
console.log(result1);
console.log(result2);
Output
[ 1, 3, 4, 5 ] -1
Using splice() method
The splice() method changes the contents of an array by removing or replacing existing elements and/or adding new elements in place.
Example: The below code removes all occurrences of an element from an Array using the splice() method in JavaScript.
function removeElement(arr, elem) {
if (!arr.includes(elem)) {
return -1;
}
for (let i = arr.length - 1; i >= 0; i--) {
if (arr[i] === elem) {
arr.splice(i, 1);
}
}
return arr;
}
const array =
[1, 2, 3, 4, 2, 5, 2];
const result1 =
removeElement(array, 2);
const result2 =
removeElement(array, 6);
console.log(result1);
console.log(result2);
Output
[ 1, 3, 4, 5 ] -1
Using forEach() method
The forEach() method will be used to iterate through each element of the array and make changes in it according to the condition passsed inside the callback function.
Example: The below code removes all occurrences of an element from an Array using the forEach() method in JavaScript.
function removeElement(arr, elem) {
if (!arr.includes(elem)) {
return -1;
}
let newArray = [];
arr.forEach(item => {
if (item !== elem) {
newArray.push(item);
}
});
return newArray;
}
const array =
[1, 2, 3, 4, 2, 5, 2];
const result1 =
removeElement(array, 2);
const result2 =
removeElement(array, 6);
console.log(result1);
console.log(result2);
Output
[ 1, 3, 4, 5 ] -1
Using reduce method
In this approach we use the reduce method to iterate over each element of the array and accumulate the elements that do not match the element to remove.
Example: The below code removes all occurrences of an element from an Array using the reduce() method in JavaScript.
function removeAllOccurrences(arr, elementToRemove) {
return arr.reduce((acc, current) => {
if (current !== elementToRemove) {
acc.push(current);
}
return acc;
}, []);
}
let array = [1, 2, 3, 4, 2, 5, 2];
let elementToRemove = 2;
let newArray = removeAllOccurrences(array, elementToRemove);
console.log(newArray);
Output
[ 1, 3, 4, 5 ]