First of all, nice work Sam.

Good idea to split up the students in two halves to prevent self-assignments. What about if the number of students is an odd number? Your code still seems to work, but a more explicit handling of this case would make the code more clear and maintainable.

I'll bring my deck of cards again this Sunday so that you can explain to me how your fancy functional code (I'm a functional fan too) works.

It is customary when you chain methods like that to start each new method on a new line, like this:

let shuffledReviewees = firstReviewers
    .map() => [Math.random(), a])
    .sort((a, b) => a[0] - b[0])
    .map(a => a[1]);

This makes it a bit more readable as you can now more clearly see the steps involved.

Maybe you can create a version where you can paste the students names into a textarea field to make it truly universal for any class. Then you can consider hosting it, for instance using a free service such as Netlify.

• Right now you are creating multiple events and you could create 1 event that executes 2 functions.

document.getElementById('leaderPicker').addEventListener('click', () => {
  leaderPicker();
  reviewersList();
});

• As you said in you slack message you have repetitions, try to clone the original array and use the new array for the forEach, every time you iterate througth student delete the element that you just used for the table.

• Doing the second task you can still have a problem, someone could have himself as reviewer.