Home »
JavaScript »
JavaScript Examples
How to find the sum of a nested array in JavaScript?
By IncludeHelp Last updated : January 21, 2024
In JavaScript, a nested array is an array that has array(s) inside an array i.e., array(s) within the array.
Problem statement
Given a nested array, you have to find all elements of all elements using JavaScript.
Finding the sum of a nested array
To find the sum of a nested array, write a function in which find the sum of all elements that are number type, check if an element is an instance of an array then again call the function itself. This process will add all elements including nested array's elements. And, then return the sum.
JavaScript code to find the sum of a nested array
The following example finds the sum of all elements of a nested arrays arr1 and arr2.
// defining function to return the
// sum of all elements of a nested array
function sumArrayElements(arr) {
var sum_elements = 0;
for (var i = 0; i < arr.length; i++) {
if (typeof arr[i] == "number") {
sum_elements += arr[i];
} else if (arr[i] instanceof Array) {
sum_elements += sumArrayElements(arr[i]);
}
}
return sum_elements;
}
// creating nested arrays
arr1 = [444, 888, [333, 999], [111]];
arr2 = [10, 20, [1, 2, 3, 4], [5, 6, [7, 8, 9]]];
// getting the sum & printing
console.log("sum of elements of arr1:", sumArrayElements(arr1));
console.log("sum of elements of arr2:", sumArrayElements(arr2));
Output
The output of the above code is:
sum of elements of arr1: 2775
sum of elements of arr2: 75
To understand the above example, you should have the basic knowledge of the following JavaScript topics: