Advanced Solution on FCC Guides does not work - "Truncate A String"

[Melvin-Viana]

Describe your problem and how to reproduce it:
Advanced solution on the freeCodeCamp guides for the "Truncate A String" challlenge does not work.
See links below.

Add a Link to the page with the problem:
https://guide.freecodecamp.org/certifications/javascript-algorithms-and-data-structures/basic-algorithm-scripting/truncate-a-string/
https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/basic-algorithm-scripting/truncate-a-string

Tell us about your browser and operating system:

• Browser Name: Google Chrome
• Browser Version: 70.0.3538.77
• Operating System: Windows 10

If possible, add a screenshot here (you can drag and drop, png, jpg, gif, etc. in this box):

[Melvin-Viana]

I copied and pasted the advanced solution and it does not work. Perhaps the challenge has been changed.

[Melvin-Viana]

This was my solution for anyone who wants to fix the FCC docs in:
https://guide.freecodecamp.org/certifications/javascript-algorithms-and-data-structures/basic-algorithm-scripting/truncate-a-string/

const truncateString=(str, num) =>
   (str.length>num)?`${str.slice(0,num)}...`:str;