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 →

For Videos Join Our Youtube Channel: Join Now

Feedback

Send your Feedback to [email protected]

Help Others, Please Share

Learn Latest Tutorials

Splunk

SPSS

Swagger

Transact-SQL

Tumblr

ReactJS

Regex

Reinforcement Learning

R Programming

RxJS

React Native

Python Design Patterns

Python Pillow

Python Turtle

Keras

Preparation

Aptitude

Reasoning

Verbal Ability

Interview Questions

Company Questions

Trending Technologies

Artificial Intelligence

AWS

Selenium

Cloud Computing

Hadoop

ReactJS

Data Science

Angular 7

Blockchain

Git

Machine Learning

DevOps

B.Tech / MCA

DBMS

Data Structures

DAA

Operating System

Computer Network

Compiler Design

Computer Organization

Discrete Mathematics

Ethical Hacking

Computer Graphics

Software Engineering

Web Technology

Cyber Security

Automata

C Programming

C++

Java

.Net

Python

Programs

Control System

Data Mining

Data Warehouse

Javatpoint Services

JavaTpoint offers too many high quality services. Mail us on [email protected], 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 [email protected]
Duration: 1 week to 2 week

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