@zamatica/logger-configuration

Configuration parameters and parsing for log levels, prefix, and color toggle. Built on @zamatica/configuration. Framework-agnostic core; NestJS-specific helpers behind the /nestjs subpath.

Install

bun add @zamatica/logger-configuration
# Optional: install only if you want the NestJS helper
bun add @nestjs/common

Registered configuration parameters

Importing LoggerConfiguration (decorator side-effect) registers three parameters with ConfigurationService:

| Key | Type | Default | Purpose | |------------------------|---------|-------------------------------|----------------------------------------------------| | LOG_LEVELS | string | "fatal,error,warn,info" | Comma-separated list of visible levels. | | LOG_PREFIX | string | falls back to env-var prefix | Prefix string for structured loggers. | | DISABLE_LOG_COLORING | boolean | false | Strip ANSI color codes from console output. |

Canonical levels: fatal, error, warn, info, debug, verbose. Unknown levels in LOG_LEVELS are silently dropped.

Quick example (framework-agnostic)

import { LoggerConfiguration } from '@zamatica/logger-configuration';
import { ConfigurationService } from '@zamatica/configuration';

ConfigurationService.setAppEnvVarPrefix('MYAPP');
ConfigurationService.initialize();

const settings = LoggerConfiguration.parseLogSettings();
// settings.levels          → ['fatal', 'error', 'warn', 'info']
// settings.prefix          → 'myapp'
// settings.disableColoring → false

NestJS subpath

For NestJS apps, map canonical levels to NestJS's LogLevel (note: NestJS uses 'log' for info-level):

import { ConsoleLogger } from '@nestjs/common';
import { mapToNestJsLogLevels } from '@zamatica/logger-configuration/nestjs';

const settings = LoggerConfiguration.parseLogSettings();
const nestLevels = mapToNestJsLogLevels(settings.levels);
const logger = new ConsoleLogger({
  prefix: settings.prefix,
  logLevels: nestLevels,
  colors: !settings.disableColoring,
});

The /nestjs subpath is the only place NestJsLogLevel types appear, so non-NestJS consumers don't pull NestJS-shaped names into their type graph.

Testing the library

Tests that use this library should re-register its parameters after ConfigurationService.__resetForTesting():

import {
  LOGGER_CONFIGURATION_PARAMETERS,
} from '@zamatica/logger-configuration';

beforeEach(() => {
  ConfigurationService.__resetForTesting();
  ConfigurationService.setAppEnvVarPrefix('TESTAPP');
  ConfigurationService.register(
    [...LOGGER_CONFIGURATION_PARAMETERS],
    'LoggerConfiguration',
  );
});