Square every digit of a number - JavaScript

We are required to write a JavaScript function that takes in a number and returns a new number in which all the digits of the original number are squared and concatenated

For example: If the number is −

9119

Then the output should be −

811181

because 9^2 is 81 and 1^2 is 1.

Example

Following is the code −

const num = 9119;
const squared = num => {
   const numStr = String(num);
   let res = '';
   for(let i = 0; i < numStr.length; i++){
      const square = Math.pow(+numStr[i], 2);
      res += square;
   };
   return res;
};
console.log(squared(num));

Output

This will produce the following output in console −

811181