Ultimate Guide to gc-stats API

The gc-stats module is an invaluable tool for monitoring and inspecting garbage collection in your Node.js applications. In this guide, we will introduce you to the gc-stats module and offer comprehensive explanations and examples of its APIs.

What is gc-stats?

The gc-stats module is essential for tracking garbage collection, offering detailed insights into different types of GC cycles, including major, minor, and incremental GCs, as well as memory usage before and after GC events.

Installation

  
    npm install gc-stats
  

Getting Started

Setting up gc-stats is straightforward:

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

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

API Examples

Tracking GC Events

You can easily track various garbage collection events:

  
    gcStats.on('stats', (stats) => {
        console.log('Type:', stats.gctype);
        console.log('Time (ms):', stats.pause / 1e6);
    });
  

Memory Usage Monitoring

Monitor memory usage before and after GC events:

  
    gcStats.on('stats', (stats) => {
        console.log('Before GC Memory Usage:', stats.before.heapUsed);
        console.log('After GC Memory Usage:', stats.after.heapUsed);
    });
  

Practical App Example

Here is an example of a small app that uses gc-stats to log and monitor memory and GC events:

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

    const app = express();
    const port = 3000;

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

    app.get('/', (req, res) => {
        res.send('Hello, World!');
        // Simulate memory usage
        let memoryLeak = [];
        for (let i = 0; i < 10000; i++) {
            memoryLeak.push(new Array(1000).fill('leak'));
        }
        memoryLeak = null;
    });

    app.listen(port, () => {
        console.log(`Server listening at http://localhost:${port}`);
    });
  

By incorporating gc-stats, you can ensure better memory management and optimized performance for your Node.js applications.

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