Nice explanation! Simple and concise. 😄
You've got a typo in your second code block:
const doubleScores = sores.map(x => x * 2)
There's a good book that's written for PHP, but provides a good understanding of higher-order functions like map and filter, written by Adam Wathan, called Refactoring to Collections.
It really helped me clean up and understand the work I do, on both front and backend layers.
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