nextjs-middleware-vitest-jsdom

What problem does it solve?

This Skill resolves the "request.headers must be an instance of Headers" error encountered when testing Next.js middleware with Vitest in a jsdom environment, enabling seamless middleware integration testing.

Core Features & Use Cases

• Mocking NextResponse: Bypasses the jsdom/edge-runtime Headers class mismatch by mocking NextResponse.next() and NextResponse.redirect().
• Preserves Testability: Allows testing of status, headers, and cookies without altering the core NextRequest object.
• Use Case: Debugging and ensuring the correct functioning of locale detection, redirect logic, or cookie handling within your Next.js middleware without relying on the edge runtime.

Quick Start

Apply the provided TypeScript mock to your Vitest setup before importing your middleware.