What is Node.js in Node.js - Interactive Quiz & Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the built-in HTTP module in Node.js.

Node.js

const http = require([1]);

Drag options to blanks, or click blank then click option'

A"fs"

B"http"

C"path"

D"express"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'fs' which is for file system operations.

Using 'express' which is a third-party framework, not built-in.

The built-in HTTP module in Node.js is imported using require("http").

2fill in blank

medium

Complete the code to create a simple HTTP server that listens on port 3000.

Node.js

http.createServer((req, res) => {
  res.writeHead(200, { 'Content-Type': 'text/plain' });
  res.end('Hello World');
}).[1](3000);

Drag options to blanks, or click blank then click option'

Astart

Bopen

Clisten

Drun

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'start' which is not a method of the server object.

Using 'run' which is not valid here.

The method to start the server listening on a port is listen.

3fill in blank

hard

Fix the error in the code to correctly import the 'fs' module.

Node.js

const fs = require([1]);

Drag options to blanks, or click blank then click option'

A"fs"

B"file-system"

C"filesystem"

D"fileSystem"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'file-system' which is not a built-in module name.

Using camelCase or other variations.

The correct module name for file system operations in Node.js is "fs".

4fill in blank

hard

Fill both blanks to create a server that responds with JSON data.

Node.js

const server = http.createServer((req, res) => {
  res.writeHead(200, { 'Content-Type': [1] });
  res.end(JSON.stringify({ message: [2] }));
});

Drag options to blanks, or click blank then click option'

A"application/json"

B"Hello"

C"text/plain"

D"World"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'text/plain' as content type when sending JSON.

Putting the content type value without quotes.

The content type for JSON data is "application/json". The message string can be any text, here 'Hello'.

5fill in blank

hard

Fill all three blanks to export a function named 'startServer' from a module.

Node.js

function [1]() {
  console.log('Server started');
}

module.exports = [2] = [3];

Drag options to blanks, or click blank then click option'

AstartServer

DserverStart

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for function and export.

Using camelCase incorrectly.

The function name and the exported name should match and be 'startServer'.

Practice

1. What is Node.js primarily used for?

easy

A. Designing graphics and images

B. Styling web pages with CSS

C. Creating static HTML pages

D. Running JavaScript code outside the browser, like on servers

Solution

1. Step 1: Understand Node.js purpose

   Node.js allows JavaScript to run on computers or servers, not just browsers.

2. Step 2: Compare options with Node.js use

   Only running JavaScript outside browsers matches Node.js's main use.

3. Final Answer:

   Running JavaScript code outside the browser, like on servers -> Option D

4. Quick Check:

   Node.js runs JavaScript outside browsers = A [OK]

Hint: Node.js runs JavaScript outside browsers [OK]

Common Mistakes:

• Confusing Node.js with CSS or HTML tools
• Thinking Node.js is for styling or graphics
• Assuming Node.js only works in browsers

2. Which of the following is the correct way to import a module in Node.js?

easy

A. import fs from 'fs';

B. require('fs');

C. include 'fs';

D. load module fs;

Solution

1. Step 1: Recall Node.js module import syntax

   Node.js uses require() function to load modules in common usage.

2. Step 2: Check each option

   require('fs'); uses require('fs'); which is correct for Node.js modules.

3. Final Answer:

   require('fs'); -> Option B

4. Quick Check:

   Node.js modules use require() = A [OK]

Hint: Use require() to load modules in Node.js [OK]

Common Mistakes:

• Using import without setup (common in older Node.js)
• Using include or load which are not valid in Node.js
• Confusing Node.js syntax with browser JavaScript

3. What will the following Node.js code output?

console.log(typeof process);

medium

A. 'object'

B. 'undefined'

C. 'function'

D. 'string'

Solution

1. Step 1: Understand the 'process' object in Node.js

   In Node.js, 'process' is a global object representing the current process.

2. Step 2: Determine the type of 'process'

   Since 'process' is an object, typeof process returns 'object'.

3. Final Answer:

   'object' -> Option A

4. Quick Check:

   typeof process = 'object' [OK]

Hint: Global Node.js objects like process are objects [OK]

Common Mistakes:

• Thinking process is undefined or a function
• Confusing process with a string or other type
• Not knowing process is built-in in Node.js

4. Identify the error in this Node.js code snippet:

const http = require('http')
http.createServer((req, res) => {
  res.write('Hello World')
  res.end()
}).listen(3000)
console.log('Server running')

medium

A. No error; code runs correctly

B. Callback function missing parameters

C. Missing semicolon after require statement

D. listen method requires a callback

Solution

1. Step 1: Review Node.js HTTP server code

   The code imports http, creates a server with a callback, writes response, ends it, and listens on port 3000.

2. Step 2: Check for syntax or logic errors

   Semicolons are optional in JavaScript; callback parameters are correct; listen can work without callback.

3. Final Answer:

   No error; code runs correctly -> Option A

4. Quick Check:

   Code is valid Node.js server setup = C [OK]

Hint: Semicolons optional; listen callback not required [OK]

Common Mistakes:

• Thinking semicolons are mandatory
• Assuming listen needs a callback
• Confusing callback parameters as missing

5. You want to build a fast web server that handles many users at once using Node.js. Which feature of Node.js helps achieve this?

hard

A. Its automatic page styling with CSS modules

B. Its built-in support for multi-threading like Java

C. Its single-threaded, event-driven architecture for handling many connections efficiently

D. Its use of synchronous blocking calls for speed

Solution

1. Step 1: Understand Node.js architecture

   Node.js uses a single thread with event-driven, non-blocking I/O to handle many connections efficiently.

2. Step 2: Evaluate options for handling many users

   Only Its single-threaded, event-driven architecture for handling many connections efficiently describes this event-driven model; others mention incorrect features.

3. Final Answer:

   Its single-threaded, event-driven architecture for handling many connections efficiently -> Option C

4. Quick Check:

   Node.js event-driven model = D [OK]

Hint: Node.js uses event-driven single thread for many users [OK]

Common Mistakes:

• Thinking Node.js uses multi-threading like Java
• Believing synchronous calls are faster
• Confusing Node.js with styling tools