# Key Value - (Map|Dictionary) - associative (memories|arrays) - Property

A map is an object that maps keys to values also known as Property.

In javascript, an object can be seen as a map of properties.

Generally:

• key value (Property) are grouped together in a collection called a map
• that cannot contain duplicate keys; each key can map to at most one value.

Also known as:

• associative memories” or “associative arrays”

A map holds a set of key/ value pairs and provides constant-time operations to store, retrieve, or test for an item in the set.