How do you extend the built-in BaseExceptionFilter to add logging while keeping default NestJS behaviour?

Q: How do you extend the built-in BaseExceptionFilter to add logging while keeping default NestJS behaviour?

import { BaseExceptionFilter } from '@nestjs/core'; @Catch() export class LoggingExceptionFilter extends BaseExceptionFilter { constructor( private readonly logger: LoggerService, applicationRef: AbstractHttpAdapter, ) { super(applicationRef); } catch(exception: unknown, host: ArgumentsHost): void { // Add pre-processing: logging, metrics, alerting if (exception instanceof HttpException) { this.logger.warn(`HTTP ${exception.getStatus()}: ${exception.message}`); } else { this.logger.error('Unhandled exception', (exception as Error)?.stack); } // Delegate to NestJS built-in response handling super.catch(exception, host); } } // Registration — requires injecting HttpAdapterHost @Module({ providers: [ { provide: APP_FILTER, useFactory: (adapter: HttpAdapterHost, logger: LoggerService) => new LoggingExceptionFilter(logger, adapter.httpAdapter), inject: [HttpAdapterHost, LoggerService], }, ], }) export class AppModule {} Extend BaseExceptionFilter when you only need to add side effects (logging, metrics) without changing the response format. Write a full custom filter when you need complete control over the response body shape. BaseExceptionFilter needs HttpAdapterHost to function — always inject it via the factory. super.catch() must be called for the default response serialization to work. This is the least invasive way to add observability without breaking the default NestJS error format.

Difficulty: 5/10

Exception handling, Custom filters, Logging integration

BaseExceptionFilter from @nestjs/core implements the built-in exception handling. Extend it, add your logic, then call super.catch() to let NestJS handle the response. Registration requires passing the HttpAdapterHost because BaseExceptionFilter needs it to access the underlying HTTP adapter.

Extending BaseExceptionFilter

When to use BaseExceptionFilter vs a full custom filter:

1
Extend BaseExceptionFilter when you only need to add side effects (logging, metrics) without changing the response format.
2

How do you extend the built-in BaseExceptionFilter to add logging while keeping default NestJS behaviour?

Difficulty: 5/10

Exception handling, Custom filters, Logging integration

BaseExceptionFilter from @nestjs/core implements the built-in exception handling. Extend it, add your logic, then call super.catch() to let NestJS handle the response. Registration requires passing the HttpAdapterHost because BaseExceptionFilter needs it to access the underlying HTTP adapter.

Extending BaseExceptionFilter

When to use BaseExceptionFilter vs a full custom filter:

1
Extend BaseExceptionFilter when you only need to add side effects (logging, metrics) without changing the response format.
2

How do you extend the built-in BaseExceptionFilter to add logging while keeping default NestJS behaviour?

BaseExceptionFilter from @nestjs/core implements the built-in exception handling. Extend it, add your logic, then call super.catch() to let NestJS handle the response. Registration requires passing the HttpAdapterHost because BaseExceptionFilter needs it to access the underlying HTTP adapter.

How do you extend the built-in BaseExceptionFilter to add logging while keeping default NestJS behaviour?

BaseExceptionFilter from @nestjs/core implements the built-in exception handling. Extend it, add your logic, then call super.catch() to let NestJS handle the response. Registration requires passing the HttpAdapterHost because BaseExceptionFilter needs it to access the underlying HTTP adapter.

Scenario Questions

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