Map
is a key/value map
Map
is a global constructor function
provides new Map().set()
to add key+value pair, get()
to read it by key
has()
tells if map has the given key
delete()
deletes the element given by the key AND map.size
reports the number of items
keys()
and values()
return iterables of the keys and values
a map can be iterated over using for-of
a map is iterable
complex types can be keys
Links
MDN page about Map.
The chapter in the specification, with all details about Map.