Middleware & Configuration Interview Questions

Middleware runs before request is completed. Enables custom code execution between request and response. Can modify response, redirect requests, add headers. Defined in middleware.ts file.

next.config.js is used for custom Next.js configuration. Supports various options like rewrites, redirects, environment variables. Exports configuration object or function.

Environment variables configured in .env files. Support different environments (.env.local, .env.production). Access via process.env. NEXT_PUBLIC_ prefix for client-side access.

Configure redirects in next.config.js using redirects array. Support permanent/temporary redirects. Handle path matching. Implement redirect conditions.

Rewrites allow URL mapping without path change. Configured in next.config.js. Support external rewrites. Handle path transformation. Maintain URL appearance.

Add custom headers using headers in next.config.js. Support security headers, CORS headers. Handle header conditions. Implement header policies.

Matcher defines paths where middleware runs. Uses path matching patterns. Support multiple matchers. Handle path exclusions. Configure middleware scope.

Customize webpack config in next.config.js. Modify loaders, plugins, optimization settings. Support module customization. Handle build process.

basePath sets base URL path for application. Useful for sub-path deployments. Handle path prefixing. Support path configuration.

Configure allowed image domains in next.config.js. Support external image optimization. Handle domain whitelist. Implement image security.

Create middleware functions. Handle request processing. Support middleware chain. Implement custom logic. Manage middleware flow.

Implement error handling in middleware. Support error recovery. Handle error responses. Implement logging. Manage error states.

Optimize build settings in next.config.js. Handle bundling options. Support optimization flags. Implement build strategies.

Compose multiple middleware functions. Handle execution order. Support middleware chaining. Implement composition patterns.

Validate configuration settings. Handle validation errors. Support schema validation. Implement validation strategies.

Create middleware tests. Handle test scenarios. Support integration testing. Implement test strategies.

Handle module aliases. Support path mapping. Configure module imports. Implement resolution strategies.

Manage middleware state. Handle state persistence. Support state sharing. Implement state patterns.

Handle response compression. Support compression options. Configure compression settings. Implement optimization strategies.

Configure CORS settings. Handle cross-origin requests. Support CORS headers. Implement security policies.

Create complex middleware solutions. Handle advanced scenarios. Support pattern composition. Implement advanced strategies.

Manage multiple configurations. Handle environment-specific settings. Support configuration versioning. Implement management strategies.

Create security-focused middleware. Handle security measures. Support security policies. Implement protection strategies.

Create logging solutions. Handle log management. Support log analysis. Implement logging strategies.

Scale configuration solutions. Handle large-scale settings. Support scaling strategies. Implement scaling patterns.

Create middleware documentation. Generate config docs. Support example usage. Implement documentation updates.

Configure deployment settings. Handle environment setup. Support deployment strategies. Implement deployment patterns.

Create comprehensive test suites. Handle test scenarios. Support testing patterns. Implement test strategies.