Welcome to the Ultimate Guide to gc-stats

Garbage collection is a crucial aspect of memory management in any programming language. In JavaScript, gc-stats is a powerful library that allows developers to gather statistics about the garbage collection process. This guide will provide a comprehensive introduction to gc-stats, exploring its various APIs with detailed examples to help you monitor and optimize your JavaScript application’s memory usage.

Getting Started with gc-stats

To begin using gc-stats, you first need to install it via npm:

  npm install gc-stats

Basic Example

Here’s a simple example to get you started:

  
    const gcStats = require('gc-stats')();
    gcStats.on('stats', (stats) => {
        console.log(stats);
    });
  

APIs and Code Snippets

1. Event: ‘stats’

This event is emitted every time a garbage collection operation is performed. The callback receives a single argument with detailed statistics.

  
    gcStats.on('stats', (stats) => {
        console.log('Garbage Collection Stats:', stats);
    });
  

2. Event: ‘error’

This event is emitted if there is an error in the gc-stats library.

  
    gcStats.on('error', (err) => {
        console.error('Error in gc-stats:', err);
    });
  

3. Working with Stats Object

The stats object contains the following key properties:

• gctype: Type of garbage collection (0 for scavenge, 1 for mark/sweep/compact, etc.)
• before: Memory usage before collection
• after: Memory usage after collection
• diff: Difference in memory usage due to collection
• pause: Duration of the GC pause

Advanced Example

Below is a more advanced example that integrates gc-stats into an Express.js application to monitor its memory usage:

  
    const express = require('express');
    const gcStats = require('gc-stats')();
    const app = express();

    gcStats.on('stats', (stats) => {
        console.log('GC Stats:', stats);
    });

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

    const PORT = process.env.PORT || 3000;
    app.listen(PORT, () => {
        console.log(`Server is running on port ${PORT}`);
    });
  

This example demonstrates a simple Express.js server that logs garbage collection statistics to the console. You can further build on this by storing these logs in a more persistent storage solution or integrating them with a monitoring service.

In conclusion, gc-stats is a valuable tool for understanding and optimizing the memory usage of your JavaScript applications. By utilizing the various APIs and examples provided in this guide, you can gain deeper insights into the garbage collection process and enhance the performance of your applications.

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