Answer 1

Maps are like normal objects but they offer builtin methods to ease the process of adding properties to them.

{a:1, b:2, c:3}
//equal
a = new Map();
a.set('a', 1);
a.set('b', 2); //...........

to iterate over it you can use a.entries() ([['a', 1], ['b', 2],....]) or a.values() ([1,2,3]) or a.keys() (['a','b','c'])....

Sets are like arrays that allow each item to appear only once....

I suggest looking up those in MDN.