Winston3 Logger with custom namespace

logger.ts

const { LOG_LEVEL, APP_ENV } = process.env;

const logFormatter = APP_ENV === 'dev'
  ? format.combine(
      winston.format.timestamp(),
      winston.format.colorize(),
      winston.format.printf((meta: any) => {
        const { level, message, timestamp, namespace, stack, ...restMeta } = meta;
        const displayNamespace = namespace ? `[${namespace}] -` : '';
        const stackMessage = stack ? `\n${stack}` : '';
        const otherMetaMessage = Object.keys(restMeta).length > 0 ? `\n${JSON.stringify(restMeta)}` : '';
        return `${timestamp} ${displayNamespace} ${level}: ${message} ${otherMetaMessage}${stackMessage}`;
      })
    )
  : format.combine(winston.format.timestamp(), winston.format.json());

const logger = winston.createLogger({
  level: LOG_LEVEL || 'debug',
  format: logFormatter,
  transports: [
    new winston.transports.Console({
      silent: APP_ENV === 'test',
    }),
  ],
});

export const Logger = (namespace?: string) => {
  if (namespace) {
    return logger.child({ namespace });
  }
  return logger;
};