Before I did this Kata I had never really understood that Javascript arrays are actually Associative Arrays. Very helpful learning experience.

Is there a clever way of doing this, or is it just brute force?

Have looked at other solutions and it seems brute force is the way ....

Why do students get full marks for submitting sentences without full stops at their end, as in "The cat. The moon... and the sliver spoon"?

Nice problem because it requires you to think a little about exactly what you are looking for.

Would be a good intermediate exercise in dealing with arrays and strings, but the addition of B# and E# was just plain annoying. Do you really need them, they're a special case that isn't mentioned in the description.

@adrian.eyre why it's like that in the first place? Anyone can easily remove the CSS and HTML and make it pure markdown, what's the problem?

Updated

Straightforward and otherwise-excellent Kata, BUT description is completely illegible if screen is set to Light mode. In Dark Mode it looks fine. Can this be fixed?

My suggestion was [ this.slice() ]. It was about returning a consistently typed value.

So return this.slice()

True! Somehow an undefined turned into a null. :)