@iamnnort/nestjs-logger

Logger module for NestJS - Simple - Informative - Pretty

Installation

npm install @iamnnort/nestjs-logger
# or
yarn add @iamnnort/nestjs-logger

Requirements

• Node.js ≥ 24

Usage

app.module.ts

import { Module } from '@nestjs/common';
import { LoggerModule, LoggerLevels } from '@iamnnort/nestjs-logger';

@Module({
  imports: [
    LoggerModule.register({
      level: LoggerLevels.INFO,
    }),
  ],
})
export class AppModule {}

main.ts

import { NestFactory } from '@nestjs/core';
import { NestExpressApplication } from '@nestjs/platform-express';
import { AppModule } from './app.module';
import { LoggerService } from '@iamnnort/nestjs-logger';

async function bootstrap() {
  const app = await NestFactory.create<NestExpressApplication>(AppModule, {
    bufferLogs: true,
  });

  const loggerService = await app.resolve(LoggerService);

  app.useLogger(loggerService);

  await app.listen(3000);
}

bootstrap();

Async configuration

Use registerAsync when the config depends on other providers (e.g. ConfigService):

import { Module } from '@nestjs/common';
import { ConfigModule, ConfigService } from '@nestjs/config';
import { LoggerModule } from '@iamnnort/nestjs-logger';

@Module({
  imports: [
    ConfigModule.forRoot(),
    LoggerModule.registerAsync({
      imports: [ConfigModule],
      inject: [ConfigService],
      useFactory: (config: ConfigService) => ({
        level: config.get('LOG_LEVEL', 'info'),
      }),
    }),
  ],
})
export class AppModule {}

Log level

Levels (most to least verbose): trace, debug, info, warn, error, fatal.

Using the logger in your code

Inject LoggerService and set the context to get a named logger:

import { Controller, Get, Post } from '@nestjs/common';
import { LoggerService } from '@iamnnort/nestjs-logger';

@Controller()
export class AppController {
  constructor(private readonly loggerService: LoggerService) {
    this.loggerService.setContext(AppController.name);
  }

  @Get()
  get() {
    this.loggerService.log('Handling GET request');
    return { success: true };
  }

  @Post()
  post() {
    this.loggerService.error('Something failed');
    return { success: false };
  }
}

Global exception filter

The module registers a global exception filter automatically. It returns proper error responses for both HTTP exceptions and unhandled errors:

// BadRequestException('Http error.')
{ "message": "Http error.", "error": "Bad Request", "statusCode": 400 }

// throw new Error('Runtime error.')
{ "message": "Something went wrong.", "error": "Internal Server Error", "statusCode": 500 }

Output

INFO (NestFactory): Application is starting...
INFO (NestApplication): Application started.
INFO (Http): GET / 200 OK (3ms)
INFO (Http): POST / 201 Created (1ms)
    request: {
      "json": {
        "id": 1234
      }
    }
ERROR (AppController): User error.
INFO (Http): POST /user-error 201 Created (1ms)
ERROR (Http): POST /http-error 500 Internal Server Error
    error: {
      "type": "Error",
      "message": "failed with status code 500"
    }

Example

An example app lives in example/. To run it:

yarn start

License

MIT © Nikita Pavets