Installing Bun & Initializing a TypeScript Project

Welcome to your first lesson. Your goal is to build Telegram bots using TypeScript and Bun.js, and this course will guide you from the ground up. To start, we need to set up your development environment. This lesson covers the essential first step: installing the Bun runtime and initializing your first TypeScript project.

Given your extensive background in front-end development, you're already familiar with the core components of a modern JavaScript project, such as package.json and tsconfig.json. Our focus here will be on how Bun simplifies and accelerates this initial setup process, particularly with its native support for TypeScript. By the end of this lesson, you will have a functional "Hello World" project running on Bun, which will serve as the foundation for all subsequent work.

An Introduction to the Bun Toolkit

Before we jump into installation, it's helpful to understand what Bun is. Unlike Node.js, which is primarily a JavaScript runtime, Bun is an all-in-one toolkit. It acts as a runtime, package manager, bundler, and test runner, all integrated into a single, high-performance binary.

For a TypeScript developer, one of its most compelling features is first-class, out-of-the-box support for .ts files. This eliminates the need for separate compilation steps or complex configurations with tools like ts-node or tsc-watch just to run your code.

To get a quick sense of why this is a significant advantage, watch this brief segment from the video "My First Time with Bun".

1. Installing Bun

Your first hands-on task is to install the Bun command-line interface (CLI) on your system. The process is straightforward and can be done using a single command in your terminal.

The video below, "Bun Crash Course", provides a good walkthrough of the installation process on different operating systems.

For your reference, here is the official installation guide with commands for macOS, Linux, and Windows. Please choose the command that is appropriate for your operating system.

Once the installation is complete, open a new terminal and run the following command to verify that Bun was installed correctly:

bun --version

You should see an output displaying the installed version number, such as 1.0.21 or higher.

2. Initializing a New Project

With Bun installed, you can now create a new project. Bun provides an initializer command, bun init, that scaffolds a new project with sensible defaults for TypeScript development.

1. Create a new directory for your project and navigate into it:

   mkdir bun-telegram-bot
   cd bun-telegram-bot
   

2. Run the initializer command:

   bun init
   

The command will prompt you for a package name and an entry point. You can accept the defaults by pressing Enter.

After the command finishes, you will see output similar to this, along with a new set of files in your directory.

3. Understanding the Project Structure

The bun init command generates a few files. As an experienced developer, you will recognize their purpose, but let's review them in the context of Bun.

• package.json: The standard project manifest file. Bun uses this for dependency management and script definitions, just like npm or yarn. Notice that it automatically adds @types/bun as a dev dependency, providing TypeScript with the necessary type definitions for Bun's APIs.
• tsconfig.json: A pre-configured TypeScript configuration file. Bun creates a tsconfig.json with modern settings optimized for its runtime, such as "module": "ESNext" and "moduleResolution": "bundler". This saves you from having to create this file from scratch.
• index.ts: The main entry point of your application, containing a simple console.log.
• bun.lockb: This is Bun's lock file. It is a binary file that serves the same purpose as package-lock.json or yarn.lock—to ensure deterministic, reproducible installs—but is significantly faster to read and write.
• .gitignore: A standard Git ignore file, pre-populated with common entries like node_modules.

4. Running Your First TypeScript File

One of the most immediate benefits of Bun is its ability to run TypeScript files directly without any explicit compilation step.

To execute the index.ts file that was created, run the following command in your terminal:

bun run index.ts

You should see the output: Hello via Bun!.

This seamless execution is a core part of the Bun developer experience. The official Quickstart guide provides a good summary of this process.

You have now successfully installed Bun and created and run your first TypeScript application. This simple project structure is the starting point from which we will build our Telegram bot.

Conclusion

In this lesson, you've taken the first practical step in your journey to building Telegram bots with Bun. You learned how to:

• Install the Bun runtime on your machine.
• Initialize a new, fully configured TypeScript project using bun init.
• Understand the files generated by the initializer, including the fast bun.lockb lock file.
• Execute a TypeScript file directly with the bun run command.

This foundational setup has prepared your development environment. In the next lesson, we will explore the key differences between the Bun and Node.js runtimes. We'll examine performance, API compatibility, and built-in tools, focusing on the aspects that will be most impactful for developing and running your Telegram bot.