Hello! Why if the given maximum string length num <= 3, then the addition of “…” not add to the string length in determining the truncated string?

Look, for example we have truncateString(“Absolutely Longer”, 2), so the num =2, 2<3, ok. Then we get “Ab”, because of .slice(0,2). But if we add 3 dots, the length’ll be 5, not 2. Who invented the rule which goes “if num <= 3, so the 3 dots won’t be counted”?