Astro 5.5 dives deep with better support for diagramming tools, improved Markdown compatibility, and type-safe sessions! Better support for diagramming tools in Markdown. Type-safe experimental sessions. Improved heading ID compatibility. Experimental: preserve order of style and script tags. To upgrade an existing project, use the automated @astrojs/upgrade CLI tool. Alternatively, upgrade manually by running the upgrade command for your package manager. Better support for diagramming tools in Markdown. Astro 5.5 introduces a new excludeLangs option in your Markdown configuration that makes it possible to skip syntax highlighting for specific language code blocks. This unlocks the ability to use tools like Mermaid and D2 without disabling syntax highlighting for other blocks. Massive thanks to Chris Chua for this contribution. Type-safe experimental sessions. Astro 5.5 adds support for proper TypeScript typing for your session data, letting you banish any mistakes. Experimental support for session storage was added in Astro 5.1, but previously all session data was untyped. Now you can define the types of your session data by extending the global App.SessionData interface in your projects src/env.d.ts file.
