import { ArgumentsHost, Catch, ConflictException, ExceptionFilter } from '@nestjs/common'; import { MongoError } from 'mongodb'; @Catch(MongoError) export class MongoExceptionFilter implements ExceptionFilter { catch(exception: MongoError, host: ArgumentsHost) { switch (exception.code) { case 11000: console.log('llave duplicada') // duplicate exception // do whatever you want here, for instance send error to client } } }