# Digit sum upto a number of digits of a number in JavaScript

JavascriptWeb DevelopmentFront End Technology

We are required to write a JavaScript function that takes in two numbers, let’s say m and n as arguments.

n will always be smaller than or equal to the number of digits present in m. The function should calculate and return the sum of first n digits of m.

For example −

If the input numbers are −

const m = 5465767;
const n = 4;

Then the output should be −

const output = 20;

because 5 + 4 + 6 + 5 = 20

## Example

Following is the code −

const m = 5465767;
const n = 4;
const digitSumUpto = (m, n) => {
if(n > String(m).length){
return 0;
};
let sum = 0;
for(let i = 0; i < n; i++){
const el = +String(m)[i];
sum += el;
};
return sum;
};
console.log(digitSumUpto(m, n));

## Output

Following is the console output −

20
Published on 19-Jan-2021 06:15:02