Logging exceptions in NestJS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of logging exceptions in a NestJS application?

Logging exceptions helps track errors that occur during app execution. It makes debugging easier and helps maintain app stability by recording what went wrong.

beginner

Which NestJS built-in service is commonly used for logging exceptions?

The built-in Logger service is used to log messages, including exceptions, in NestJS applications.

intermediate

How do you log an exception message using NestJS Logger inside a catch block?

Use Logger.error(error.message, error.stack) inside the catch block to log the error message and stack trace.

intermediate

What is the benefit of logging the stack trace along with the exception message?

The stack trace shows the exact path the code took before the error happened, helping developers find the root cause faster.

advanced

How can you create a custom exception filter in NestJS to log exceptions globally?

Create a class implementing <code>ExceptionFilter</code>, use <code>Logger</code> inside the <code>catch()</code> method to log errors, and apply it globally with <code>app.useGlobalFilters()</code>.

Which NestJS class is used to log error messages?

A Logger

B ExceptionFilter

C HttpException

D Middleware

The Logger class is designed for logging messages including errors.

What method of Logger logs error messages?

A log()

B warn()

C error()

D debug()

Logger.error() is used specifically to log error messages.

Why include stack trace when logging exceptions?

A To improve app speed

B To restart the app automatically

C To hide error details

D To find where the error happened

Stack trace helps developers find the exact location of the error.

How do you apply a custom exception filter globally in NestJS?

A Add it to controllers only

B Use app.useGlobalFilters()

C Import it in main.ts without applying

D Use app.useMiddleware()

app.useGlobalFilters() applies exception filters globally.

What is the main benefit of logging exceptions?

A To track and debug errors

B To ignore errors

C To slow down the app

D To prevent user access

Logging exceptions helps track and debug errors effectively.

Explain how to log exceptions in a NestJS application using the Logger service.

Think about how you catch errors and what info you want to save.

Describe how to create and apply a global exception filter in NestJS for logging errors.

Consider how NestJS handles exceptions and where to hook logging.