Node.js os and process Modules

What is os and process Modules in Node.js?

The os module reports information about the machine — CPUs, memory, platform, uptime. process describes the running Node process and lets you read environment variables, handle signals and exit cleanly.

os and process Modules example

import os from 'node:os';

os.cpus().length;         // logical CPU count — used to size a cluster
os.totalmem() / 1e9;      // total RAM in GB
os.freemem();
os.platform();            // 'linux' | 'darwin' | 'win32'
os.hostname();
os.tmpdir();

process.memoryUsage().heapUsed;   // bytes of heap in use
process.uptime();                 // seconds since start
process.cwd();                    // current working directory

Key points to remember

• os.cpus().length decides how many workers a cluster or PM2 should run.
• process.memoryUsage() is the first thing to check when a leak is suspected.
• os.tmpdir() gives the correct temporary directory on every platform.