Introduction to Kosher Logger

Kosher-logger is a robust logging library for JavaScript applications. It supports various logging levels and provides flexible configuration options to fit your project needs. In this guide, we will explore the essential APIs of kosher-logger with code snippets and a comprehensive example application.

Installation

  npm install kosher-logger

Basic Usage

  const Logger = require('kosher-logger');
  const logger = new Logger();

  logger.info('This is an info message');
  logger.warn('This is a warning message');
  logger.error('This is an error message');

Advanced Configuration

You can customize your logger with various options:

  const Logger = require('kosher-logger');
  const logger = new Logger({
    level: 'debug',
    format: Logger.Format.JSON,
    transports: [
      new Logger.transports.Console(),
      new Logger.transports.File({ filename: 'combined.log' }),
    ],
  });

  logger.debug('This is a debug message with advanced configuration');

Logging Levels

Kosher-logger supports multiple logging levels:

  logger.debug('Debug message');
  logger.info('Info message');
  logger.warn('Warning message');
  logger.error('Error message');
  logger.fatal('Fatal message');

Custom Transports

Create custom transports to handle logs differently:

  class CustomTransport {
    log(info) {
      // Custom logic goes here
      console.log("CustomTransport: ", info.message);
    }
  }

  const logger = new Logger({
    transports: [new CustomTransport()],
  });

  logger.info('This uses a custom transport');

Using Middleware

Integrate kosher-logger with middleware in an Express app:

  const express = require('express');
  const Logger = require('kosher-logger');
  const logger = new Logger();

  const app = express();

  app.use((req, res, next) => {
    logger.info(`${req.method} ${req.url}`);
    next();
  });

  app.get('/', (req, res) => {
    res.send('Hello World');
  });

  app.listen(3000, () => {
    logger.info('Server is running on port 3000');
  });

Application Example

Here is a complete example demonstrating various features of kosher-logger within an application:

  const Logger = require('kosher-logger');
  const express = require('express');

  const logger = new Logger({
    level: 'info',
    transports: [
      new Logger.transports.Console(),
      new Logger.transports.File({ filename: 'app.log' }),
    ],
  });

  const app = express();

  app.use((req, res, next) => {
    logger.info(`${req.method} ${req.url}`);
    next();
  });

  app.get('/', (req, res) => {
    logger.info('Home route accessed');
    res.send('Welcome to the Kosher Logger App');
  });

  app.get('/error', (req, res) => {
    logger.error('An error occurred on /error route');
    res.status(500).send('This is an error route');
  });

  app.listen(3000, () => {
    logger.info('Application is running on port 3000');
  });

With these examples, you can see how flexible and powerful kosher-logger can be for your logging needs. Give it a try in your next project.

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