Global exception filters in NestJS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a global exception filter in NestJS?

A global exception filter in NestJS is a special class that catches and handles all exceptions thrown in the application, allowing centralized error handling.

beginner

How do you apply a global exception filter in a NestJS application?

You apply a global exception filter by using the app.useGlobalFilters(new YourExceptionFilter()) method inside the main bootstrap function.

intermediate

What method must be implemented in a NestJS exception filter class?

The exception filter class must implement the <code>catch(exception: any, host: ArgumentsHost)</code> method to handle exceptions.

intermediate

Why use a global exception filter instead of local filters?

Global exception filters handle errors across the whole app, reducing repeated code and ensuring consistent error responses everywhere.

advanced

What is the role of ArgumentsHost in a global exception filter?

ArgumentsHost provides access to the current request and response objects, letting the filter send custom responses based on the context (HTTP, WebSocket, etc.).

Which method is used to register a global exception filter in NestJS?

A app.setExceptionFilter()

B app.registerExceptionFilter()

C app.addGlobalFilter()

D app.useGlobalFilters()

The correct method to register a global exception filter is app.useGlobalFilters().

What does the catch method in an exception filter receive as arguments?

A request and response

B exception and ArgumentsHost

C error and next function

D exception and next function

The catch method receives the thrown exception and an ArgumentsHost to access context.

Global exception filters in NestJS are best for:

A Handling errors app-wide in one place

B Handling errors only in one controller

C Logging only without modifying responses

D Replacing middleware

Global filters handle exceptions across the entire app, centralizing error handling.

Which interface should a global exception filter class implement?

A ExceptionFilter

B HttpException

C MiddlewareConsumer

D PipeTransform

Exception filters must implement the ExceptionFilter interface.

What can you access through ArgumentsHost in a global exception filter?

A Application configuration

B Only the exception message

C Request and response objects

D Database connection

ArgumentsHost gives access to request and response objects to customize error responses.

Explain how to create and apply a global exception filter in NestJS.

Think about the class, method, and where to register it.

Describe the benefits of using a global exception filter compared to local filters in NestJS.

Consider maintenance and consistency advantages.