# Finding the sum of all common elements within arrays using JavaScript

JavascriptWeb DevelopmentFront End Technology

## Problem

We are required to write a JavaScript function that takes in three arrays of numbers. Our function should return the sum of all those numbers that are common in all three arrays.

## Example

Following is the code −

Live Demo

const arr1 = [4, 4, 5, 8, 3];
const arr2 = [7, 3, 7, 4, 1];
const arr3 = [11, 0, 7, 3, 4];
const sumCommon = (arr1 = [], arr2 = [], arr3 = []) => {
let sum = 0;
for(let i = 0; i < arr1.length; i++){
const el = arr1[i];
const ind2 = arr2.indexOf(el);
const ind3 = arr3.indexOf(el);
if(ind2 !== -1 && ind3 !== -1){
arr2.splice(ind2, 1);
arr3.splice(ind3, 1);
sum += el;
};
};
return sum;
};
console.log(sumCommon(arr1, arr2, arr3));

## Output

7
Published on 21-Apr-2021 06:39:48