Map: Basics

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 MDN page about Map.
spec The chapter in the specification, with all details about Map.