# Checking digit sum of smallest number in the array in JavaScript

We are required to write a JavaScript function that takes in an array of numbers as the first and the only argument. The function should first pick the smallest number from the array and then calculate the sum of all the digits of the number.

If the digit sum of that number is even, we should return true, false otherwise.

For example −

If the input array is −

const arr = [12, 657, 23, 56, 34, 678, 42];

Then the output should be

const output = false;

because the smallest number in the array is 12 and its digit sum is 1 + 2 = 3, odd.

## Example

The code for this will be −

Live Demo

const arr = [12, 657, 23, 56, 34, 678, 42];
const addDigits = (num = 1, sum = 0) => {
if(!num){
return sum;
};
return addDigits(Math.floor(num / 10), sum + (num % 10));
};
const findSmallest = (arr = []) => arr.reduce((acc, val) => Math.min(acc, val));
const checkSmallestSum = (arr = []) => {
const smallest = findSmallest(arr);
return smallestSum % 2 === 0;
};
console.log(checkSmallestSum(arr));

## Output

And the output in the console will be −

false

Updated on: 27-Feb-2021

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