Your understand how to use the various built-in methods for arrays and strings
Your understand of how to use loops
Things to improve
Obviously code indentation (although it's a simple) which immensely improves readability
(for this purpose we will be using standard js to solve the issue once and for ever)
I know naming variables is sometimes the hardest part but with practice you will get better.
If a function is a bit complex try to break it down into more sub-functions by building helper functions
Things I like
arrays
andstrings
Things to improve