Function to determine what color shirt somebody should wear to a football game depending on what seat they have
I see 2 points where you can work to increase the quality of your code.


simplify some conditions check 
get rid of comments


simplify some conditions check

Consider the following code:

/* Case 3: Section is two letters (No numbers) */
else if (section.length == 2 &amp;&amp; section.charAt(0) &gt;= 'A' &amp;&amp; section.charAt(0) &lt;= 'Z'  &amp;&amp;
       section.charAt(1) &gt;= 'A' &amp;&amp; section.charAt(1) &lt;= 'Z') {


I think you could make it shorter with just a regular expression:

else if (section.match(^[A-Z]{2}$)) {


It is not just short and fast to read, but, in this case, it show you what is the "rule" that the string should satisfy.

get rid of comments

Your code is full of comments, and that made it difficult to reed.

Consider that many developer, me included, don't trust the comments and read it just when something weird happened. And in this case too there are very few times the comments helps.

The reason is you should update the comments as you update the code, but this never happened as it is more work and you don't have time.

Compilers or interpeter never care the comments.

The other point is that the developers could read and understand the code, and your effort should put in made the code readable for human beings.

Let me show some examples.

  /* Case 1: Section is a special section */
  if (section.includes("TER") || section.includes("WC") || section.includes("EC")) {


Consider the followhing change. As you can see you don't need the comment any more.

if (isASpecialSection(section)) {

...

function isASpecialSection(section) {
    return section.includes("TER") || section.includes("WC") || section.includes("EC");
}


Another example:

/* Case 2: Section is a single letter (No numbers) */
else if  (section.length === 1) {


Even the condition is short, you should use the same approach, as it is not clear in which case you are here.

Look at the comment, it "lied", because you just check that the string have length 1, not that is only letters. Maybe you don't have the case today, but data could change.

So remove the comment and change the check:

else if (section.match(/^[A-Z]$/)) {


Not all comments are bad, you should avoid those comments that tell what the code does, because you can read the code and so it is a waste of time for the developers that read your code.

Too many comments like in your code make difficult to read the code.
To put all those comments you break the indentation.

Try to make your code more readable by using proper names or functions to encapsulate complex conditions.

Naming is hard and take time, I know, but it pay back.