Defining Basic JavaScript Terms: map, filter, and reduce

For those learning JavaScript, Jim Nielsen has a helpful post on the difference between map, filter, and reduce:
“Understanding what APIs do in a language is one way to understand code… Understanding why APIs are named the way they are in a language is another plane of understanding code.”
Another good JavaScript-related resource comes from Sia Karamalegos who explains how to discover and visualize all the JavaScript downloaded and used (or unused) on a site with a new tool: Lighthouse Treemap.