JavaScript Maps
A map stores key-value pairs in which the keys may be of any sort of data. The keys' original placement order is retained by a Map.
| Method | Description |
|---|---|
| new Map() | Generates a new Map. |
| set() | Adds a new key-value pair to the Map object. |
| get() | Returns the value associated with a specified key. |
| delete() | Removes the key-value pair associated with the specified key from the Map object. |
| has() | Returns a boolean indicating whether the specified key exists in the Map object. |
| forEach() | Each key/value pair in a Map is called by a different function. |
| entries() | Returns an iterator for the key-value pairs in the Map object. |
| Property | Description |
|---|---|
| size | Returns the number of key-value pairs in the Map object. |
Create map method
You can create a JavaScript Map by:
- Giving a new Map an Array ().
- Create a map using Map.set ().
new Map() Method
The new Map() method in JavaScript is used to generate a new Map object, which is a collection of key-value pairs with any type of key, including objects and functions, as a possible value.
set() Method
The Map object's built-in set() function in JavaScript allows you to add new key-value pairs to the map or change the value of an existing key.
get() Method
The get() function of the Map object in JavaScript is a built-in method that obtains the value connected to a certain key in the map.
delete() Method
The delete() function of the Map object in JavaScript removes the key-value pair connected to a specified key from the map.
has() Method
The has() function of the Map object in JavaScript is a built-in method that returns a boolean indicating whether or not a given key is present in the map.
forEach() Method
The forEach() method of the Map object in JavaScript enables you to repeatedly loop over all the key-value pairs in the map and run a callback function for each pair.
entries() Method
The forEach() method of the Map object in JavaScript enables you to repeatedly loop over all the key-value pairs in the map and run a callback function for each pair.
size Property
The size property of the Map object in JavaScript is a built-in property that returns the number of key-value pairs in the map.