TL;DR

ElysiaJS now supports streaming responses with backpressure and handles Range headers for efficient file/blob delivery, improving performance for large data transfers.

New

• Streaming Responses: Implement server-sent events and real-time data updates.
• Range Headers: Enable partial content requests for files (improves download speeds).

Fixes Worth Knowing

• Dynamic imports within .guard functions now correctly register routes.
• HTML imports are now compatible with Bun (a JavaScript runtime).
• Error responses that return Promises are now handled correctly.
• Cookie configurations are merged, resolving potential validation issues.

Before You Upgrade

If you are using Bun, ensure your HTML imports are correctly configured to take advantage of the fix.

TL;DR

ElysiaJS 0.8 focuses on API stability and performance improvements, introducing a powerful Macro API (customizable plugin logic) and new lifecycle hooks for more control over request processing.

Breaking

• afterHandle Early Return: afterHandle no longer short-circuits the request.
• derive Context Changes: derive is now accessed via decorator['derive'] instead of directly from the context.

New

• Macro API: Enables highly customizable plugin logic with full type safety.
• New Lifecycle Hooks: resolve (safe derive) and mapResponse (custom response transformation) offer finer-grained control.
• Error Function: A new error() function simplifies returning status codes with values, improving type inference for tools like Eden (code analysis).

Fixes Worth Knowing

• Validation errors are now returned as JSON with detailed information, improving debugging.
• Improved handling of large files (videos) with automatic content-range header addition.

Before You Upgrade

• Review any code relying on early returns within afterHandle and adjust accordingly.
• Update references

TL;DR

Elysia 0.3 introduces Elysia Fn, enabling you to directly call backend functions from the frontend with full type safety and autocompletion, significantly accelerating development.

Breaking

• OpenAPI 2.x to 3.0.3: API definitions have been updated, potentially requiring changes to existing integrations.
• derive Removed: This feature is no longer available.
• Context Store Change: Internal context storage has moved from context.store[SYMBOL] to meta[SYMBOL].

New

• Elysia Fn: Call backend functions directly from the frontend with type safety. (Backend-to-frontend communication)
• File Uploads: Native support for file uploads via multipart/formdata with validation using File and Files types.
• Eden Rework: Eden now offers three function types (treaty, fn, fetch) for improved scalability and type inference.

Fixes Worth Knowing

• Improved TypeScript inference during plugin registration.
• Resolved potential build errors when using declaration: true in tsconfig.json.

Before You Upgrade