What is a Map ?
A map is the representation of certain elements which are mapped with some values.
What is a Map in Javascript ?
A map is a javascript object used to map the keys with values.
Map stores each element in key-value pair.
Syntax :
new Map([iterable])
Iterable:
It defines an array and other iterable object whose elements are in the form of key-value pair.
Example :
<script>
var map = new Map();
map.set("FName","Abdul");
map.set("LName","Kalaam");
map.set("Sex","Male");
map.set("Occupation","Scientist");
map.set("Location","India");
map.set("Language","Tamil");
console.log(map);
</script>
Output :
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How does map works in javascript ?
Map object cannot contain duplicate keys.
Map object can contain duplicate values.
Key-value pair can be of any type since it allows both object and primitive values.
Map object iterates its elements in insertion order.
Methods of Map Object
A map object is a collection of key-value pairs with some of the common methods listed below.
| Sno | Methods / Function | Description |
|---|---|---|
| 1 | clear() | clear() method removes all the elements from a Map object. |
| 2 | delete() | delete() method deletes the specified element from a Map object. |
| 3 | entries() | entries() method returns an object of Map iterator that contains the key-value pair for each element. |
| 4 | forEach() | forEach() method executes the specified function once for each key/value pair. |
| 5 | get() | get() method returns the value of the specified key. |
| 6 | has() | has() method indicates whether the map object contains the specified key element. |
| 7 | keys() | keys() method returns an object of Map iterator that contains the keys for each element. |
| 8 | set() | set() method adds or updates the key-value pairs to Map object. |
| 9 | values | values() method returns an object of Map iterator that contains the values for each element. |