Return Early Pattern for Functions code problem

I see another solution for this challenge with if and it works, but i think that i can use case.

Where is the problem in my code?

Your code so far

// Setup
function abTest(a, b) {
  // Only change code below this line

  switch (abTest){
  case a < 0:
  return undefined;
  case 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

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Link to the challenge:

It’s the way you are trying to use the switch statement
This translate to

if (abTest === (a < 0)) {
   return undefined;
} else if (abTest === (b < 0)) {
   return undefined;

For starting you don’t have a variable abTest defined in your code

You may want to change approach here

Also, check the documentation on switch: