Setup

Since v3.3.0, you should put ConsoleLogger exported from nestlogged package to the NestFactory.create call.

import { ConsoleLogger } from 'nestlogged';

const app = await NestFactory.create(AppModule, {
  logger: new ConsoleLogger(),
});

The definition of ConsoleLogger is 100% same with ConsoleLogger from @nestjs/common, so you can just use it normally.

This new ConsoleLogger handles additional request scope parameter internally.

Method Logging

Basic

Basic of NestLogged is to add a log at the call and return time of the method.

You can use LoggedRoute decorator for methods in Controller, and LoggedFunction for methods in other classes like service to simply add call and return logs and print out the logs.

// Controller
import { LoggedRoute } from 'nestlogged';
import { Controller, Get } from '@nestjs/common';

@Controller('cats')
export class CatsController {
    @LoggedRoute()
    @Get()
    public async findAllCats() {
        // ...
    }
}
/*
LoggedRoute Log Message:
[Nest] 4208  - 01/12/2024, 5:16:02 PM     LOG [CatsController] ID=[...] | CatsController.findAllCats: HIT ENDPOINT CatsController.findAllCats (CatsController::/[GET])
...
[Nest] 4208  - 01/12/2024, 5:16:02 PM     LOG [CatsController] ID=[...] | CatsController.findAllCats: RETURNED ENDPOINT CatsController.findAllCats (CatsController::/[GET])
*/

// Service
import { LoggedFunction } from 'nestlogged';
import { Injectable } from '@nestjs/common';

@Injectable()
export class CatsService {
    @LoggedFunction()
    public async findAllCats() {
        // ...
    }
}
/*
LoggedFunction Log Message:
[Nest] 23564  - 01/12/2024, 5:17:40 PM     LOG [CatsService] CatsService.findAllCats: HIT FUNCTION CatsService.findAllCats
...
[Nest] 23564  - 01/12/2024, 5:17:40 PM     LOG [CatsService] CatsService.findAllCats: RETURNED FUNCTION CatsService.findAllCats
*/

Decorator Options

You can put option object to set decorator's settings.

Both decorator takes some type of option. You can see the definition of option and default values in below.

interface OverrideBuildOptions {
  callLogLevel: LogLevel | 'skip';
  returnLogLevel: LogLevel | 'skip';
  errorLogLevel: LogLevel | 'skip';
  /** @deprecated use `callLogLevel: 'skip'` instead */
  skipCallLog: boolean;
  /** @deprecated use `returnLogLevel: 'skip'` instead */
  skipReturnLog: boolean;
  /** @deprecated use `errorLogLevel: 'skip'` instead */
  skipErrorLog: boolean;
}

const defaultOverrideBuildOptions: OverrideBuildOptions = {
  callLogLevel: 'log',
  returnLogLevel: 'log',
  errorLogLevel: 'error',
  skipCallLog: false,
  skipReturnLog: false,
  skipErrorLog: false,
}

export function LoggedFunction<F extends Array<any>, R>(
  options?: Partial<OverrideBuildOptions>
) {
  ...
}

export function LoggedRoute<F extends Array<any>, R>(
  route?: string,
  options?: Partial<OverrideBuildOptions>
) {
  ...
}

Logger Initialization

For LoggedFunction and LoggedRoute decorator, it will initialize new ScopedLogger if it does not exists as logger property in the class. This initialization is processed on the first call of decorated function.

ScopedLogger is the new class extending Logger from @nestjs/common, adding ability to add scope and scope id to each logs. But you don't have to worry about it, it's not a whole new system. It's completely same as usual logging, and internal code will do all the "scope" processes.

If you want to know more about scoped logging, check Logger Injection & Scoped Logging.