What we got wrong about HTTP imports

🌈 Abstract

The article discusses the evolution of Deno's module system, highlighting the challenges faced with the initial approach of using HTTP imports and the solutions introduced in Deno 2.

🙋 Q&A

[01] Challenges with HTTP imports in Deno

1. What were the key issues with using HTTP imports in Deno?

• Long URLs clutter codebases, especially in larger projects
• Managing long URLs and versions becomes increasingly tedious as projects grow
• URLs lack semantic versioning, making it hard to manage dependencies
• The decentralized module system caused reliability problems, as many modules were hosted on random websites or personal servers, leading to uptime issues

2. How did Deno address these issues?

• Introduced Import Maps to allow for short and memorable specifiers and better version management across files
• Created JSR, a centralized repository that understands semantic versioning, to address the duplicate dependency problem and improve reliability

[02] Deno's new module system approach

1. How does the new module system in Deno 2 work?

• Deno still supports HTTP imports, but recommends using Import Maps and JSR for better scalability and management
• Import Maps allow for short and memorable specifiers and version management across files
• JSR is a centralized repository that understands semantic versioning, providing a reliable and centralized way to share and consume JavaScript and TypeScript modules

2. What are the key benefits of the new module system in Deno 2?

• Simplifies module management and dependency resolution
• Provides a reliable and centralized way to share and consume modules
• Inherits the benefits of HTTP imports, such as granular downloads of only the code being imported
• Automatically keeps dependencies up to date (unless pinned by a lockfile)

3. How does the new module system compare to the previous approach?

• The new system is more complex than the initial HTTP imports approach, but the benefits are considered worth the tradeoffs
• Existing Deno scripts with HTTP imports will continue to work, but the new approach with Import Maps and JSR is now recommended for larger projects