Welcome to the Comprehensive Guide to gc-stats

gc-stats is a powerful library for Node.js developers that provides detailed statistics on garbage collection (GC) activities. Understanding GC can help developers optimize memory usage and improve application performance.

Introduction to gc-stats

gc-stats is a native Node.js module that hooks into the V8 garbage collector, allowing you to monitor and retrieve detailed statistics about garbage collection events. The library can be particularly useful for performance tuning and monitoring memory usage in production applications.

Installation

  npm install gc-stats

Using gc-stats: Useful API Examples

The following sections provide useful API examples to demonstrate how to use gc-stats in your Node.js application.

Basic Setup

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

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

Handling Different GC Types

gc-stats categorizes GC events into different types, such as Scavenge, MarkSweepCompact, and IncrementalMarking. Here’s how to handle different GC types:

  
    gcStats.on('stats', (stats) => {
      switch (stats.gctype) {
        case 1:
          console.log('Scavenge GC:', stats);
          break;
        case 2:
          console.log('MarkSweepCompact GC:', stats);
          break;
        case 4:
          console.log('IncrementalMarking GC:', stats);
          break;
        default:
          console.log('Other GC type:', stats);
      }
    });
  

Advanced Usage with Interval Monitoring

Monitoring GC events at regular intervals can help in identifying memory leaks and optimizing performance.

  
    setInterval(() => {
      global.gc();
    }, 60000); // Trigger GC every 60 seconds

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

Comprehensive Application Example

Here is an example of a Node.js application that integrates gc-stats to monitor and log garbage collection statistics.

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

    const app = express();

    gcStats.on('stats', (stats) => {
      fs.appendFile('gc-log.txt', JSON.stringify(stats) + '\n', (err) => {
        if (err) {
          console.error('Error writing to log file:', err);
        }
      });
    });

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

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

By integrating gc-stats with applications, developers can gain valuable insights into memory management and garbage collection behavior, ultimately leading to more efficient and performant applications.

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