No.1:
Carefully reread the directions here
Return the truncated string with a ... ending.
Then take a look at what you wrote in the else clause.
No.2:
You need to look carefully at this test case
console.log(truncateString("A-tisket a-tasket A green and yellow basket", "A-tisket a-tasket A green and yellow basket".length + 2));
You should notice that the string length is shorter than the num argument.
The challenge wants you to only truncate the string if the str length is greater than the num argument.
For this test case, your code should return the string.
Not the truncated string.
You need to modify your code to account for this test case.
Hope that helps!
Sidenote: It doesn’t look like you are using this here so you can probably just delete it