21th of 38 Questions.
What is the difference between map.keys(), map.values(), and map.entries()? What do they return?
map.keys() returns an iterator over keys; map.values() returns an iterator over values; map.entries() returns an iterator over [key, value] pairs. All follow the iterator protocol.
These methods allow iterating over Map entries in different ways. map.entries() is the default iterator for Map, which is why for (const [k,v] of map) works.