How do you apply global middleware, pipes, guards, or interceptors in NestJS?
Use app.useGlobalPipes(), app.useGlobalGuards(), app.useGlobalInterceptors(), and app.useGlobalFilters(). These bypass DI so they cannot inject services. To use DI, register globals inside a module using the APP_GUARD, APP_PIPE, APP_INTERCEPTOR, or APP_FILTER tokens.
Two ways to register global enhancers
Key difference:
app.useGlobal*() — simple but cannot inject services; use for dependency-free enhancers.
APP_* tokens — registered inside the DI container; supports full constructor injection.
The APP_* token approach is preferred for any enhancer that has dependencies.