ARUS Framework

A high-performance, explicit backend framework for TypeScript.

Design Constraints

• Explicitness First: Everything is predictable. No decorators, no DI, no middleware chains.
• Performance Target: Within ±5% of Fastify in hello-world & JSON benchmarks.
• Runtime Agnostic: Core works in Node.js, Bun, Deno, Cloudflare Workers.
• Linear Execution: Requests flow through handlers sequentially. No branching.
• Sync Hot Path: Pipelines determine async/sync at startup for optimal performance.

Routing Limitations

ARUS Router is O(1) static routing only. It does not support:

• Parameterized routes (e.g., /users/:id)
• Wildcards (e.g., /files/*)
• Regex patterns

Use static paths like /users/123. For dynamic routing, handle in handlers by parsing ctx.request.url.

Path matching is strict: /users ≠ /users/.

Common Mistakes

• Async Handlers: Declare as async function to ensure correct pipeline execution. Sync pipelines will throw in development if a handler returns a Promise.
• Context Mutability: ctx.request is readonly by convention. ctx.response is write-only. ctx.state is user-owned.
• Error Handling: Errors are stored in ctx.error. Do not throw in handlers—set ctx.error instead.
• Adapter Bodies: FetchAdapter buffers bodies by default. For streaming, implement custom adapter.

Benchmarks

Run npm run bench for autocannon comparisons with Fastify.