How to check if a string is a valid hex color representation?

Question

For example:

AA33FF = valid hex color

Z34FF9 = invalid hex color (has Z in it)

AA33FF11 = invalid hex color (h

Answer 1

Add a length check to make sure that you don't get a false positive

function isValidHex(testNum){
  let validHex = false;
  let numLength = testNum.length;
  let parsedNum = parseInt(testNum, 16);
  if(!isNan(parsedNum) && parsedNum.length===numLength){
     validHex = true;
  }
  return validHex;

}