TypeScript Map

TypeScript map is a new data structure added in ES6 version of JavaScript. It allows us to store data in a key-value pair and remembers the original insertion order of the keys similar to other programming languages. In TypeScript map, we can use any value either as a key or as a value.

Create Map

We can create a map as below.

Map methods

The TypeScript map methods are listed below.

SN	Methods	Descriptions
1.	map.set(key, value)	It is used to add entries in the map.
2.	map.get(key)	It is used to retrieve entries from the map. It returns undefined if the key does not exist in the map.
3.	map.has(key)	It returns true if the key is present in the map. Otherwise, it returns false.
4.	map.delete(key)	It is used to remove the entries by the key.
5.	map.size()	It is used to returns the size of the map.
6.	map.clear()	It removes everything from the map.

Example

We can understand the map methods from the following example.

let map = new Map();

map.set('1', 'abhishek');   
map.set(1, 'www.javatpoint.com');     
map.set(true, 'bool1'); 
map.set('2', 'ajay');

console.log( "Value1= " +map.get(1)   ); 
console.log("Value2= " + map.get('1') ); 
console.log( "Key is Present= " +map.has(3) ); 
console.log( "Size= " +map.size ); 
console.log( "Delete value= " +map.delete(1) ); 
console.log( "New Size= " +map.size );

Output:

When we execute the above code snippet, it returns the following output.

Iterating Map Data

We can iterate over map keys or values or entries by using 'for...of' loop. The following example helps to understand it more clearly.

Example

let ageMapping = new Map();
 
ageMapping.set("Rakesh", 40);
ageMapping.set("Abhishek", 25);
ageMapping.set("Amit", 30);
 
//Iterate over map keys
for (let key of ageMapping.keys()) {
    console.log("Map Keys= " +key);        
}
//Iterate over map values
for (let value of ageMapping.values()) {
    console.log("Map Values= " +value);    
}
console.log("The Map Enteries are: "); 
//Iterate over map entries
for (let entry of ageMapping.entries()) {
    console.log(entry[0], entry[1]); 
}

Output:

Next TopicTypeScript Set

← prev next →

Help Others, Please Share

Learn Latest Tutorials

UML

ANN

ES6

Flutter

Selenium Py

Firebase

Cobol

Ansible

Mockito

Talend

Azure

SharePoint

Preparation

Aptitude

Reasoning

Verbal A.

Interview

Company

Trending Technologies

AWS

Selenium

Cloud

Hadoop

ReactJS

D. Science

Angular 7

Blockchain

Git

DevOps

B.Tech / MCA

DBMS

DAA

C. Network

Compiler D.

COA

D. Math.

E. Hacking

C. Graphics

Software E.

Web Tech.

Cyber Sec.

Automata

C++

Java

.Net

Python

Programs

Control S.

Data Mining

Javatpoint Services

JavaTpoint offers too many high quality services. Mail us on hr@javatpoint.com, to get more information about given services.

Website Designing
Website Development
Java Development
PHP Development
WordPress
Graphic Designing
Logo
Digital Marketing
On Page and Off Page SEO
PPC
Content Development
Corporate Training
Classroom and Online Training
Data Entry

Training For College Campus

JavaTpoint offers college campus training on Core Java, Advance Java, .Net, Android, Hadoop, PHP, Web Technology and Python. Please mail your requirement at hr@javatpoint.com.
Duration: 1 week to 2 week

^{Like/Subscribe us for latest updates or newsletter}