Logging for TypeScript: Winston Library

What is Winston and why is it needed?

Winston is a popular logging library for TypeScript and JavaScript. It provides a flexible logging system with support for multiple transports (console output, file, database, HTTP), logging levels, and message formatting. In large projects, logging is critical for debugging, monitoring, and auditing user or system actions. Winston allows you to structure logs, filter them by importance, and save them in a format convenient for analysis.

How to install Winston in TypeScript

To install, run the command in the terminal:

npm install winston

It is also recommended to install types for TypeScript:

npm install --save-dev @types/winston

Main features of Winston

• Logging levels: error, warn, info, verbose, debug, silly (configurable).
• Transports: Console, File, HTTP, MongoDB, Syslog, and others.
• Formatting: JSON, plain text, timestamps, colors.
• Asynchronicity: does not block the main thread.
• Custom profiles: creating your own levels and transports.

Code example in TypeScript

import winston from 'winston';

const logger = winston.createLogger({  level: 'info',  format: winston.format.json(),  transports: [    new winston.transports.Console({      format: winston.format.simple(),    }),    new winston.transports.File({ filename: 'error.log', level: 'error' }),    new winston.transports.File({ filename: 'combined.log' }),  ],});

logger.info('Application started');logger.error('Database connection error');

This code creates a logger that writes all messages of level info and above to the console, errors to error.log, and all logs to combined.log.

When to use Winston

Winston is suitable for any server-side Node.js applications (Express, NestJS, Koa), microservices, CLI utilities, and complex scripts. It is especially useful in production environments where centralized log storage, file rotation, and integration with monitoring systems (ELK, Splunk) are required. For simple projects, you can use the built-in console.log, but Winston provides control and scalability.