os module for system information in Node.js - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this code using os module?

Consider this Node.js code snippet using the os module. What will be the output of the os.platform() call?

Node.js

import os from 'os';
console.log(os.platform());

A "win32" (on Windows), "linux" (on Linux), or "darwin" (on macOS) depending on the OS

B "Windows", "Linux", or "MacOS" as full names

C The CPU architecture like "x64" or "arm"

D The hostname of the computer

💡 Hint

The os.platform() method returns a short string identifying the operating system platform.

The os.platform() method returns a string like "win32", "linux", or "darwin" to identify the OS platform in a short form.

❓ Predict Output

intermediate

What does os.cpus() return?

Given this code snippet, what is the type of the value returned by os.cpus()?

Node.js

import os from 'os';
const cpus = os.cpus();
console.log(typeof cpus);

A "number" representing the count of CPUs

B "string" describing the CPU model

C "object" because it returns an array of CPU info objects

D "undefined" because os.cpus() does not exist

💡 Hint

Check the Node.js os module docs for the return type of os.cpus().

The os.cpus() method returns an array of objects, each describing a CPU core.

❓ component_behavior

advanced

How does os.freemem() behave in a running Node.js app?

If you call os.freemem() multiple times in a Node.js app, what can you expect about the values returned?

A The values always return zero

B The values remain constant during the app lifetime

C The values increase steadily as the app runs

D The values may change over time as memory usage changes

💡 Hint

Think about how free memory changes as programs run.

The free memory reported by os.freemem() can change as the system allocates and frees memory.

📝 Syntax

advanced

Which option correctly imports and uses os.totalmem() in Node.js ES modules?

Choose the correct code snippet to import the os module and log total system memory in bytes.

A

import * as os from 'os';
console.log(os.totalmem());

B

const os = require('os');
console.log(os.totalmem());

C

import { totalmem } from 'os';
console.log(totalmem());

D

import os from 'os';
console.log(os.totalmem());

💡 Hint

Node.js ES modules use import syntax with default or named imports.

In ES modules, import * as os from 'os'; imports the os module as a namespace. Then os.totalmem() calls the function.

🔧 Debug

expert

Why does this code throw TypeError: os.uptime is not a function?

Given this code snippet, why does it throw a TypeError?

Node.js

import { uptime } from 'os';
console.log(os.uptime());

A Because uptime is not a function in the os module

B Because os is not defined; only uptime was imported, so os.uptime() is undefined

C Because import syntax is invalid for os module

D Because uptime requires arguments but none were given

💡 Hint

Check what variables are defined after import.

The code imports only uptime but tries to call os.uptime(). The variable os is not defined, causing the error.