Unlike Node, a monolithic project, Deno is organized into a collection of Rust crates. In this talk, Anthony Campolo summarizes Deno's architecture and how it was created.
Episode Summary
This episode dives into the architecture and internal workings of Deno, a secure runtime for JavaScript and TypeScript. The speakers, Anthony Campolo and Bartek Iwańczuk, provide insights into Deno’s modular structure, which is built using Rust crates. They discuss key components such as the V8 engine, TypeScript compiler, and custom-built tools like SWC (Speedy Web Compiler) and dprint. The talks highlight Deno’s approach to improving performance, enhancing security, and maintaining browser compatibility. The speakers also touch on Deno’s development process, its rapid release cycle, and the ongoing efforts to modularize the runtime further. The episode concludes with an invitation for developers to contribute to the Deno project, emphasizing its accessibility for both Rust and TypeScript developers.
Chapters
00:00 - Introduction and Overview of Deno
This chapter introduces the speakers and provides a high-level overview of Deno. Anthony Campolo begins by explaining that Deno is an anagram of Node and discusses the pronunciation debate. He then outlines Deno’s core principles, including security by default, TypeScript support, and a single executable file. The chapter also touches on Deno’s history, mentioning Ryan Dahl’s initial concept of V8 Worker and the decision to use Rust instead of Go for implementation. This section sets the stage for a deeper dive into Deno’s architecture and components.
04:59 - Deno’s Architecture and Core Components
This chapter covers the architecture of Deno, explaining its modular design using Rust crates. Bartek Iwańczuk takes over, describing the main components of the Deno binary: the JavaScript engine (V8), event loop (Tokio), TypeScript compiler, and the module graph system. He goes into detail about Rusty V8, a layer of bindings between V8 and Rust, and Deno core, which provides abstractions like ops and resources. The chapter also covers the module graph and caching system, explaining how Deno fetches, analyzes, and caches dependencies efficiently. This section provides a comprehensive overview of Deno’s internal structure and how its various components interact.
17:54 - TypeScript Integration and Performance Optimizations
This chapter focuses on Deno’s integration with TypeScript and the performance optimizations implemented. Bartek discusses the challenges of incorporating TypeScript, including its synchronous API and performance issues. He explains how Deno uses V8 snapshots to improve TypeScript compiler startup time. The chapter then introduces SWC (Speedy Web Compiler), a fast JavaScript and TypeScript compiler written in Rust. Bartek describes how SWC has been instrumental in moving more of Deno’s infrastructure from JavaScript to Rust, resulting in significant performance improvements. This section highlights Deno’s approach to balancing TypeScript support with runtime efficiency.
54:37 - Built-in Tools: Formatter, Linter, and Documentation Generator
This chapter covers the built-in tools that come with Deno, including the code formatter (dprint), linter (Deno lint), and documentation generator (DenoDoc). Bartek explains how these tools were developed or chosen, emphasizing the decision to create Rust-based alternatives to existing JavaScript tools for improved performance. He discusses the opinionated nature of these tools, particularly the formatter and linter, which don’t allow for customization. The chapter also touches on the modular design of these tools, which are developed as separate Rust crates and then integrated into Deno. This section showcases Deno’s approach to providing a comprehensive development toolkit within a single binary.
62:45 - Future Directions and Contributing to Deno
The final chapter discusses the future directions of Deno and encourages community contributions. Bartek explains the ongoing efforts to further modularize Deno, potentially allowing users to create custom runtimes with only the components they need. He emphasizes the accessibility of contributing to Deno, noting that the project includes both Rust and TypeScript code. The speakers invite developers to join the Deno community through GitHub or Discord, highlighting the opportunity to contribute to various aspects of the project, from core functionality to the standard library. This section concludes the talk by outlining Deno’s collaborative development model and future vision.