Return Early Pattern for Functions : Better Solutions Please

I don’t know how to solve this challenge except in this way.
According to the challenge, it says; Modify the function abTest so that if a or b are less than 0 the function will immediately exit with a value of undefined.
I would love if someone can help. Thanks.

Your code so far


// Setup
function abTest(a, b) {
  // Only change code below this line
  if (a < 0 || b < 0) {
    return "undefined";
  }
  
  
  // Only change code above this line

  return Math.round(Math.pow(Math.sqrt(a) + Math.sqrt(b), 2));
}

// Change values below to test your code
console.log(abTest(-2,2));

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.131 Safari/537.36.

Link to the challenge:
https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/basic-javascript/return-early-pattern-for-functions

You are returning a string, instead in JavaScript undefined (without quotes) is a specific value

Thanks, I just solved it.