pureblood | Penetration Testing Framework created for Hackers / | Security Testing library

I wrote this JS code yesterday for a school project, and everything was okay(ish). The site showed the key/value I wanted to add to the object. Although today, when I reloaded the server and the site, all the values were undefined or "muggle". I refreshed the page many times, and sometimes it works, but the next time it's undefined again.

So the code should be do something like this:

1.Fetch two JSON files, one is a list of students and the other is just family names

2.Create two arrays from the data

3.Check every single student's last name if it's on the list or not

4.Decide that the student is pure, half or muggle

5.Add the value to the student object

6.Show on the website

I know that it's something to do with the call order of the functions and something is wrong where I use the include() method two check the names. But unfortunately, I couldn't find out what. Here is the JS code: