Recursively adding digits of a number in JavaScript

We are required to write a JavaScript function that takes in a number and recursively adds the digits of the number until the result is not a single digit number.

For example, If the number is −

54563

Then the output should be 5, because,

= 5 + 4 + 5 + 6 + 3 = 23 = 2 + 3 = 5

Example

The code for this will be −

const num = 54563; const addRecursively = num => {    if(num < 10){       return num;    };    let sum = 0;    while(num !== 0) {       sum += (num%10);       num = parseInt(num/10);    };    return addRecursively(sum); }; console.log(addRecursively(num));

Output

The output in the console −

3