express-lens

A lightweight, plug-and-play monitoring package for Express.js applications. It silently tracks your application's metrics and logs a concise analytics summary inline to the console for every HTTP request.

Features

• Zero setup: Just plug it into your Express app as a middleware.
• Inline Analytics Logs: View realtime metrics for every request without any dashboards getting in the way.
• Performance Tracking: Measures response times, average request durations, and memory (RSS) usage.
• Error Tracking: Keeps a tally of request errors (HTTP 400+).

Installation

You can install express-lens using npm or yarn:

npm install express-lens

yarn add express-lens

Usage

Simply require the middleware and add it to your Express app before declaring your routes.

const express = require('express');
const monitor = require('express-lens');

const app = express();

// Add the monitor middleware
app.use(monitor());

// Your routes
app.post('/users', (req, res) => {
  res.status(201).json({ message: 'User created' });
});

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

When a request hits your server, you will see a log similar to this in your console:

Configuration

The monitor middleware takes an optional configuration object.

app.use(monitor({
  logAnalytics: true // Default is true. Set to false to disable console logging.
}));

License

MIT

Developed by github/codebygarv