TypeScript is a popular superset of JavaScript that adds optional static typing and other features to help developers write more robust and maintainable code. Nest.js, on the other hand, is a powerful Node.js framework that provides a structured and scalable approach to building server-side applications.

In this tutorial, we'll introduce you to both TypeScript and Nest.js and show you how to get started with building your own server-side applications using these tools.


Installing TypeScript

Before we can get started with Nest.js, we need to install TypeScript. You can do this using npm, the Node.js package manager, by running the following command:

npm install -g typescript

Creating a New Nest.js Project

Once TypeScript is installed, we can use it to create a new Nest.js project. To do this, we'll use the Nest.js CLI, which you can install by running the following command: 

npm install -g @nestjs/cli

With the CLI installed, we can create a new Nest.js project by running the following command:

nest new my-project

This will create a new Nest.js project in a directory named "my-project".


Adding TypeScript Support to Nest.js

By default, Nest.js projects are built using JavaScript. However, we can easily add TypeScript support by running the following command:

npm install --save-dev @nestjs/platform-express @nestjs/mapped-types @types/express

This will install the necessary packages and TypeScript typings to enable TypeScript support in our project.


Writing TypeScript Code

With TypeScript support enabled, we can now start writing our Nest.js application using TypeScript. Nest.js provides a powerful set of decorators and other tools to help us write clean, modular, and maintainable code.

Here's an example of a simple Nest.js controller written in TypeScript:

import { Controller, Get } from '@nestjs/common';

@Controller('hello')
export class HelloController {
  @Get()
  getHello(): string {
    return 'Hello World!';
  }
}


Compiling and Running the Application

Finally, we need to compile our TypeScript code into JavaScript so that it can be run by Node.js. To do this, we can use the TypeScript compiler, which we installed earlier.

To compile our code, we can run the following command:

tsc

This will compile our TypeScript code into JavaScript and place it in a "dist" directory.

To run the application, we can use the Node.js command-line interface and run the following command:

node dist/main.js

This will start our Nest.js application and make it available at http://localhost:3000/hello.


Conclusion

In this tutorial, we introduced you to TypeScript and Nest.js and showed you how to get started with building your own server-side applications using these tools. While we only scratched the surface of what is possible with these technologies, we hope that this tutorial has given you a good foundation to build on. Happy coding!