What is namespace in Typescript ?

Last Updated : 17 Mar, 2025

In TypeScript, a namespace is a way to organize code logically and prevent naming conflicts between identifiers. It allows developers to group related functionalities, such as interfaces, classes, functions, and variables, within a dedicated scope.

Namespaces are particularly useful for structuring large applications, avoiding global scope pollution, and maintaining a clear hierarchy.

Declaring and Using a Namespace in TypeScript

Here’s a simple example demonstrating how to create and use a namespace in TypeScript:

JavaScript

namespace Geometry {   export class Circle {     constructor(public radius: number) {}      area(): number {       return Math.PI * this.radius ** 2;     }   } } const circle = new Geometry.Circle(5); console.log(circle.area());

Namespace Declaration: The Geometry namespace encapsulates the Circle class, ensuring that its members are scoped within this namespace.
Class Definition: The Circle class has a constructor to set the radius and a method area() to calculate the area of the circle.
Object Instantiation: An instance of Circle is created with a radius of 5.
Method Invocation: The area() method is called on the circle instance to compute and log the area.

Output:

78.53981633974483

More Examples of Namespace in TypeScript

Declaring and Accessing a Simple Namespace

JavaScript

namespace MyNamespace {   export function myFunction() {     console.log('This is my function in MyNamespace');   } }  MyNamespace.myFunction();

Namespace Declaration: MyNamespace is defined using the namespace keyword, encapsulating the myFunction function.
Function Definition: myFunction logs a message to the console.
Export Keyword: The export keyword makes myFunction accessible outside the MyNamespace namespace.
Function Invocation: myFunction is called using dot notation: MyNamespace.myFunction().

Output:

This is my function in MyNamespac

Declaring and Accessing a Nested Namespace

JavaScript

namespace MyNamespace {   export namespace MySubNamespace {     export function myFunction() {       console.log('This is my function in MySubNamespace');     }   } }  MyNamespace.MySubNamespace.myFunction();

Nested Namespace Declaration: MySubNamespace is defined inside MyNamespace, creating a hierarchical structure.
Function Definition: myFunction logs a message to the console.
Export Keyword: The export keyword makes myFunction accessible outside the MySubNamespace namespace.
Function Invocation: myFunction is called using dot notation: MyNamespace.MySubNamespace.myFunction().

Output:

"This is my function in MySubNamespace"

Benefits of Using Namespaces

Organize Code: Namespaces help group related code together, making it easier to manage and maintain.
Prevent Conflicts: They avoid naming issues by keeping your code in its own unique space.
Hide Details: You can keep internal code hidden and only show the necessary parts to the outside world.
Break Down Code: Namespaces let you divide a large project into smaller, easier-to-manage pieces.