TypeScript: How to Create and Use a Interface

An interface in TypeScript defines the blueprint of an object, ensuring type safety and consistency in your code.

Typescript interfaces are a key feature that allows you to define the structure of an object, ensuring type safety in your application. Interfaces can describe properties, methods, and their expected types, making your code robust and self-documenting. In this post, we’ll explore how to create a TypeScript interface and demonstrate its usage with a simple example.

Define a UserInterface

Here’s how we can define a UserInterface in TypeScript to represent a user object. It includes three properties (id, name, age) and a method getMessage that returns a string.

interface UserInterface {
  id: string;        // Unique identifier for the user
  name: string;      // Name of the user
  age: number;       // Age of the user

  // Method that returns a custom message
  getMessage(): string;
}

Explanation

1. id, name, and age are fields that describe the structure of a user object. Their types are string, string, and number, respectively.
2. getMessage is a method that returns a string. It doesn’t take any parameters in this example but could be extended for more functionality.

Usage Example of UserInterface

Here’s how we can implement and use the UserInterface in a TypeScript application: