[Updated] Top 120+ Node Js Interview (MCQ) With Answers - April 2024

Q1. What is the primary use of Node.js?

1. Front-end web development.
2. Building server-side applications.
3. Database management.
4. None of the above.

Q2. How does Node.js handle user requests efficiently?

1. Creates a new thread for each request.
2. Uses a multi-threaded architecture.
3. Processes requests asynchronously.
4. Blocks the main thread until a request is complete.

Q3. Key features of Node.js?

1. Blocking I/O operations.
2. Single-threaded and non-scalable.
3. Asynchronous and event-driven.
4. Dependent on Python for execution.

Q4. How does Node.js ensure fast code execution, and which JavaScript engine does it use?

1. Uses the V8 JavaScript engine for faster code execution.
2. Utilizes a custom JavaScript engine developed by Node.js.
3. Relies on the user's web browser's JavaScript engine.
4. Does not execute JavaScript code.

Q5. Main difference between using Node.js and linking HTML with JavaScript?

1. Node.js is for server-side JavaScript, while linking HTML and writing JS is for client-side.
2. Node.js is a server-side runtime; linking HTML/JS is for client-side in a web browser.
3. No significant difference; both approaches are interchangeable.
4. Node.js is for client-side scripts; linking HTML is for server-side scripting.

Q6. How does Node.js manage I/O operations without blocking the main thread?

1. Blocks the main thread until I/O operations complete.
2. Creates a new thread for each I/O operation.
3. Handles I/O operations asynchronously.
4. Does not support I/O operations.

Q7. What is the role of the event loop in Node.js, and how does it work?

1. Blocks incoming events until the main thread is available.
2. Processes events sequentially in a single thread.
3. Invokes callback functions for events asynchronously.
4. Creates a new thread for each event.

Q8. Significance of using the V8 JavaScript Runtime engine?

1. Makes code execution slower due to engine limitations.
2. Uses a custom JavaScript engine for better performance.
3. Relies on the user's web browser for JavaScript execution.
4. Enhances code execution speed and efficiency.

Q9. Why is JavaScript commonly used in Node.js development, and what advantages does it offer?

1. JavaScript is used for front-end development only.
2. JavaScript is not well-suited for server-side programming.
3. JavaScript allows for code sharing between client and server.
4. JavaScript is not widely known among developers.

Q10. How does Node.js handle long-running tasks while maintaining responsiveness to incoming requests?

1. Blocks incoming requests until long-running tasks complete.
2. Creates a separate thread for each long-running task.
3. Performs long-running tasks asynchronously using worker threads or external processes.
4. Does not support long-running tasks.

Q11. Why does Node.js not buffer data, and how does it handle data output?

1. Node.js buffers all data to improve performance.
2. Node.js does not handle data output.
3. Node.js outputs data in chunks and does not buffer it.
4. Node.js buffers data and processes it sequentially.

Q12. How does Node.js handle long-running tasks while maintaining responsiveness to incoming requests?

1. Performs long-running tasks asynchronously using worker threads or external processes.
2. Blocks incoming requests until long-running tasks complete.
3. Creates a separate thread for each long-running task.
4. Does not support long-running tasks.

Q13. Primary benefit of using Node.js for real-time applications, such as chat applications or online gaming?

1. Node.js is not suitable for real-time applications.
2. Node.js offers high latency for real-time communication.
3. Node.js can only handle static content delivery.
4. Node.js provides low latency and rapid data exchange for real-time applications.

Q14. How does Node.js maintain a responsive main thread while handling multiple concurrent connections?

1. Creates a new thread for each connection.
2. Uses a multi-threaded architecture.
3. Blocks the main thread until connections are complete.
4. Handles connections asynchronously, allowing the main thread to remain responsive.

Q15. How does Node.js handle CPU-intensive tasks while maintaining its non-blocking nature?

1. Blocks incoming requests until CPU-intensive tasks complete.
2. Performs CPU-intensive tasks asynchronously using worker threads or external processes.
3. Creates multiple threads for CPU-intensive tasks.
4. Does not support CPU-intensive tasks.

Q16. Node.js code to print "Hello, Node.js!"?

console.log("Hello, Node.js!");

1. Error in the code.
2. Correctly prints "Hello, Node.js!" to the console.
3. Prints "Hello, World!" instead.
4. Results in an infinite loop.

Q17. Advantages of using Node.js for real-time chat applications?

1. Node.js provides low latency, scalability, and event-driven architecture for real-time chat applications.
2. Node.js is not suitable for real-time chat applications.
3. Node.js offers high latency for real-time communication.
4. Node.js can only be used for static content delivery.

Q18. Main advantage of Node.js in handling multiple concurrent connections?

1. Creates a new thread for each connection.
2. Blocks incoming connections until previous ones are complete.
3. Handles connections asynchronously, allowing the main thread to remain responsive.
4. Relies on external libraries to manage connections.

Q19. How does Node.js ensure that event handling does not block the main thread?

1. Blocks the main thread until events are complete.
2. Creates a separate thread for each event.
3. Relies on external libraries for event handling.
4. Processes events in the event loop asynchronously, invoking callback functions when events are ready.

Q20. Why is it important for Node.js to handle I/O operations asynchronously, and how does it achieve this efficiency?

1. Handling I/O operations synchronously improves performance.
2. Handling I/O operations asynchronously ensures the main thread remains responsive.
3. Node.js does not handle I/O operations.
4. Node.js relies on external libraries for I/O operations.

Q21. Syntax for creating single-line and multi-line comments in Node.js?

1. Single-line comments start with '#', and multi-line comments are enclosed in //.
2. Single-line comments start with '//' or '#', and multi-line comments are enclosed in '/*' and '*/'.
3. Single-line comments start with '--', and multi-line comments are enclosed in '//'.
4. Node.js does not support comments.

// This is a single-line comment in Node.js
const a = 'Hello';

/*
This is a
multi-line comment
in Node.js
*/
const b = 'World';

Q22. Primary benefit of Node.js's non-blocking (asynchronous) I/O model?

1. Simplifies error handling.
2. Allows for parallel processing of requests.
3. Reduces the need for event-driven programming.
4. Enforces a strict single-threaded execution model.

Q23. How does Node.js handle concurrency, and what is its advantage in this regard?

1. Node.js uses multi-threading for concurrency.
2. Node.js creates a new process for each concurrent request.
3. Node.js handles concurrency through event-driven, single-threaded architecture, which is memory-efficient and scalable.
4. Node.js relies on external libraries for concurrency management.

Q24. Advantages of using Node.js for building RESTful APIs compared to traditional server-side technologies?

1. Node.js does not support the development of RESTful APIs.
2. Node.js offers better performance but lacks scalability.
3. Node.js provides high performance, scalability, and a unified JavaScript ecosystem for both front-end and back-end development.
4. Node.js is limited to building SOAP APIs.

Q25. How does Node.js handle memory consumption and why is it considered memory-efficient?

1. Excessive memory consumption, making it memory-intensive.
2. Relies on garbage collection for memory management.
3. Uses a small, fixed amount of memory per connection and recycles memory efficiently.
4. No memory management capabilities.

Q26. Explain callback functions in Node.js and their role in asynchronous programming.

1. Not used in Node.js.
2. Used for blocking I/O operations.
3. Functions passed as arguments, executed later for asynchronous programming.
4. Used for defining variables in Node.js.

Q27. "Event-driven" in Node.js and its importance for scalability?

1. Node.js is not event-driven.
2. Node.js only supports events related to user interactions.
3. Node.js responds to events, such as incoming requests or data, by invoking appropriate callback functions. This allows for efficient and scalable handling of multiple concurrent events.
4. Node.js relies on external event-handling libraries.

Q28. Difference between traditional server-side technologies and Node.js in handling concurrent connections?

1. Traditional: Multiple threads per connection. Node.js: Single thread.
2. Traditional: Single thread. Node.js: Creates a new thread for each connection.
3. Both use a single thread for all connections.
4. Neither supports concurrent connections.

Q29. How does Node.js handle long-running tasks without blocking the main thread?

1. Pauses the main thread until tasks complete.
2. Creates a new thread for each task.
3. Splits tasks into smaller asynchronous operations for responsiveness.
4. Node.js does not support long-running tasks.

Q30. Primary advantage of using an event-driven architecture in Node.js, especially for real-time applications?

1. Reduces CPU usage.
2. Simplifies error handling.
3. Provides low latency and scalability for real-time applications by efficiently managing asynchronous events.
4. Not suitable for real-time applications.

Q31. Why is Node.js considered highly scalable despite its single-threaded nature?

1. Creates multiple threads for handling requests.
2. Blocks requests until previous ones are complete.
3. Processes requests sequentially.
4. Handles requests asynchronously, allowing it to scale.

Q32. Purpose of the Node.js setup process

1. To uninstall Node.js.
2. To configure NPM.
3. To install and configure Node.js for development or server-side applications.
4. To update system drivers.

Q33. Role of the "npm install" command

1. Used to create a new Node.js project.
2. Used to install Node.js itself.
3. Used to install project dependencies listed in the "package.json" file.
4. Used to run JavaScript code in the browser.

Q34. Difference between local and global installation of Node.js packages?

1. Local installs globally; global installs within project.
2. Local installs within project; global installs on system.
3. Both install within project directory.
4. Both install globally on the system.

Q35. Role of NPM in Node.js?

1. Used for front-end development only.
2. Not essential for Node.js development.
3. Simplifies package management, dependency tracking, and distribution of Node.js modules.
4. Used exclusively for server-side programming.

Q36. How to check if Node.js is installed on your system?

1. Run "node --check" in the terminal.
2. Check the system control panel.
3. Inspect the browser settings.
4. Run "node -v" in the terminal.

Q37. What is NPM, and why is it important in Node.js development?

1. Manages network profiles.
2. Node.js programming module.
3. Package manager for Node.js, simplifying dependency management and workflows.
4. Web browser extension.

Q38. How to install Node.js and NPM on your system?

1. Download Node.js installer from the official website and follow installation instructions.
2. Download and run the "npm" command.
3. Use a web browser to access Node.js files.
4. Manually copy Node.js files to your system.

Q39. How to manage multiple versions of Node.js on your system?

1. Manually renaming Node.js installation folders.
2. Using a package manager other than NPM.
3. Using a version manager like "nvm" (Node Version Manager) for Unix-based systems or "nvm-windows" for Windows.
4. Creating separate user accounts for each Node.js version.

Q40. Role of Node.js Package Manager (NPM) during the setup process?

1. NPM manages the Node.js source code.
2. NPM helps install Node.js itself.
3. NPM is not essential for Node.js development.
4. NPM manages project dependencies and libraries, crucial for Node.js development.

Q41. Advantages of using "nvm" for Node.js?

1. Not recommended for Node.js.
2. Allows easy switching and concurrent management of multiple Node.js versions.
3. Useful only for web development, not server-side applications.
4. Less stable than direct Node.js installations.

nvm install 14.17.0   # Install Node.js version 14.17.0
nvm use 14.17.0       # Switch to Node.js version 14.17.0
nvm install 16.3.0    # Install Node.js version 16.3.0
nvm use 16.3.0        # Switch to Node.js version 16.3.0

Q42. How to update Node.js to a newer version with NPM?

1. Use the "npm update node" command.
2. Node.js cannot be updated using NPM.
3. Run "npm install -g npm" to update Node.js and NPM to their latest versions.
4. Manually download and install the new Node.js version from the official website.

Q43. What does the "node" command do in Node.js?

1. Create new projects.
2. Install Node.js.
3. Run server-side JavaScript files.
4. Manage project dependencies.

node myScript.js

Q44. What is the purpose of the "package.json" file in a Node.js project?

1. Store project documentation.
2. Define metadata, including name, version, dependencies, and scripts.
3. Store test cases and unit tests.
4. Configure server settings.

{
	"name": "my-node-project",
	"version": "1.0.0",
	"description": "A sample Node.js project",
	"main": "index.js",
	"scripts": {
	"start": "node index.js",
	"test": "mocha"
	},
	"dependencies": {
	"express": "^4.17.1",
	"lodash": "^4.17.21"
	},
	"devDependencies": {
	"mocha": "^9.0.0"
	},
	"author": "Your Name",
	"license": "MIT"
}

Q45. How to specify Node.js version in "package.json" for compatibility?

1. In "scripts" section.
2. In "engines" field.
3. In "dependencies" section.
4. In "name" field.

Q46. Purpose of "node_modules" directory in Node.js project?

1. For Node.js documentation.
2. For storing configuration files.
3. Stores installed dependencies, enabling the project to use external libraries.
4. Temporary directory during Node.js installation.

Q47. Role of "npx" command in Node.js?

1. Create new Node.js projects.
2. Install Node.js modules globally.
3. Execute Node.js packages or binaries without global installation for using the latest versions.
4. Manage project dependencies.

npx create-react-app my-app

Q48. Create a new Node.js project using "npm init"?

1. Automatically generates all required configuration files.
2. Prompts for project details like name, version, description, entry point, test command, and repository URL.
3. Creates a new project with default settings for later manual configuration.
4. Not used for creating new Node.js projects.

Q49. Purpose of "package-lock.json" in a Node.js project?

1. Stores user authentication data.
2. Autogenerated file tracking exact versions of dependencies for consistent installations.
3. Defines project metadata.
4. Backup of "package.json."

Q50. Globally install Node.js package using "npm install -g"?

1. Install project-specific dependencies.
2. Uninstall Node.js packages globally.
3. Install Node.js package or tool globally, accessible from the command line.
4. Not a valid npm command.

Q51. Purpose of NODE_ENV in Node.js?

1. Specify Node.js installations location.
2. Set the working directory for a Node.js app.
3. Indicate the environment (e.g., "development," "production") to configure behavior.
4. Used for internal debugging; avoid modification.

if (process.env.NODE_ENV === 'production') {
    // Production error handling
    app.use((err, req, res, next) => {
    res.status(500).send('Something went wrong');
    });
} else {
    // Development and other environment error handling
    app.use((err, req, res, next) => {
    res.status(500).send(err.stack);
    });
}

Q52. Category of String, Number, and Boolean in Node.js?

1. Primitives
2. Objects

var name = "John"; // String
var age = 30; // Number
var isTrue = true; // Boolean

Q53. Primitive data type in Node.js?

1. Array
2. Function
3. Symbol

const uniqueSymbol = Symbol('unique');

Q54. Category of Function and Array in Node.js?

1. Primitives
2. Objects

function greet() {
    console.log("Hello!");
}
    
const numbers = [1, 2, 3, 4];

Q55. Data type for holding a large integer value in Node.js?

1. String
2. Number
3. BigInt

const bigIntValue = 1234567890123456789012345678901234567890n;

Q56. Data type for an unassigned variable in Node.js?

1. Undefined
2. Null
3. Symbol

let uninitializedVariable;
console.log(uninitializedVariable); // Outputs: undefined

Q57. What is a String in Node.js?

1. A sequence of numeric values
2. A sequence of Unicode characters that can be wrapped in single or double quotation marks
3. A special data type used only for dates and times
4. An array of characters

const myString = "Hello, Node.js!";

Q58. Which function is used to split a string and return an array of strings?

1. charAt()
2. Concat()
3. Match()
4. Split()

const myString = "apple,banana,cherry";
const fruitsArray = myString.split(",");

console.log(fruitsArray); // Output: ["apple", "banana", "cherry"]
console.log(myString);    // Output: "apple,banana,cherry"

Q59. Which function is used to get the character at a specific index in a string?

1. Concat()
2. charAt()
3. indexOf()
4. Match()

const myString = "Node.js";

console.log(myString.charAt(1));    // Output: "o" (character at index 1)
console.log(myString.charAt(10));   // Output: "" (no character at index 10, so an empty string is returned)
console.log(myString.charAt(-1));   // Output: "" (no character at index -1, so an empty string is returned)

Q60. Which function is useful to join an array of strings separated by a comma (,) operator?

1. Split()
2. Concat()
3. Match()
4. Join()

const fruits = ["apple", "banana", "cherry"];

// Use the join method to join array elements with an empty separator
const result = fruits.join("");
console.log(result); // Output: "applebananacherry"

// Use the join method to join array elements with a comma separator
const result1 = fruits.join(",");
console.log(result1); // Output: "apple,banana,cherry"

Q61. What is the output of the following code?

const str = "Node.js";
console.log(str.charAt(7));

1. ""
2. "Node.js"
3. Error
4. "s"

Q62. Which function should you use to concatenate two strings without spaces in Node.js?

1. str.concat()
2. str.join()
3. str.concat('')
4. str.splice()

Q63. Output of the following code in Node.js?

const str = "apple,banana,cherry";
const result = str.split(",");
console.log(result.length);

1. 3
2. 18
3. 1
4. 15

Q64. What's true about the `match()` function in Node.js?

1. Always returns an array.
2. Returns the first occurrence of the matched string.
3. Not a built-in function in Node.js.
4. Returns null if no match is found.

Q65. What is the output of the following code?

const str = "Node.js";
console.log(str.slice(1, -1));

1. "ode.j"
2. "ode."
3. Error
4. Undefined

console.log(str.slice(1, -1));     // Output: "ode.j"
console.log(str.substring(1, -1)); // Output: "N"


The second argument -1 is treated as if it were 0 because negative indices are interpreted as 0.
So, it will extract a substring from index 1 (the second character, "o") to index 0 (the first character, "N").

Q66. What is the output of the following code?

const str = "Node.js";
console.log(str.charAt(-1));

1. "N"
2. Error
3. ""
4. "."

Q67. Which function finds the last index of a character or substring in a string?

1. str.lastIndexOf()
2. str.charAt()
3. str.indexOf()
4. str.search()

Q68. What is the output of the following code?

const str = "apple,banana,cherry";
const result = str.split("a");
console.log(result.length);

1. 5
2. 2
3. 1
4. 4

const str = "apple,banana,cherry";
const result = str.split("a");
console.log(result); // [ '', 'pple,b', 'n', 'n', ',cherry' ]

Q69. What is the output of the following code?

const str = "Node.js";
console.log(str.lastIndexOf("o", 1));

1. 0
2. 1
3. -1
4. 3

const str = "Node.js Node.js";
console.log(str.lastIndexOf("o"));    // Output: 9 (index of the last "o" in the string)
console.log(str.lastIndexOf("o", 0)); // Output: -1 (searching before the start of the string, so not found)
console.log(str.lastIndexOf("o", 1)); // Output: 1 (searching from index 1, which is the second character "o")
console.log(str.lastIndexOf("o", 2)); // Output: 1 (searching from index 2, which is still the second character "o")
console.log(str.lastIndexOf("o", 3)); // Output: 1 (searching from index 3, which is still the second character "o")
console.log(str.lastIndexOf("z"));    // Output: -1 (the letter "z" is not in the string)
console.log(str.lastIndexOf("z", 1)); // Output: -1 (searching from index 1, but the letter "z" is not in the string)

Q70. Output of the following code?

const str = "Node.js";
console.log(str.lastIndexOf("o"));

1. 0
2. 1
3. 4
4. -1

Q71. Which of the following functions is used to find the index of a specific character in a string?

1. Concat()
2. charAt()
3. indexOf()
4. Split()

const myString = "Hello, Node.js!";
const index = myString.indexOf("Node");
console.log(index) //7

Q72. Which function is useful to match multiple strings?

1. Concat()
2. charAt()
3. Match()
4. indexOf()

const text = "Hello, Node.js!";
const pattern = /Node.js/;
const result = text.match(pattern);
console.log(result[0]); //Node.js
console.log(result); // [ 'Node.js', index: 7, input: 'Hello, Node.js!', groups: undefined ]

Q73. Which function finds the index of the first occurrence of a character or substring in a string?

1. str.lastIndex()
2. str.firstIndex()
3. str.indexOf()
4. str.search()

const str = "Hello, world! Welcome to Node.js";
const indexOfWorld = str.indexOf("world");
console.log(indexOfWorld); // Output: 7
console.log("Original String:", str); // Output: Original String: Hello, world! Welcome to Node.js
console.log("Substring:", str.substring(indexOfWorld, indexOfWorld + 5)); // Output: Substring: world!
console.log("Substring Length:", str.substring(indexOfWorld, indexOfWorld + 5).length); // Output: Substring Length: 6
console.log("Character at Index 0:", str.charAt(0)); // Output: Character at Index 0: H
console.log("Character at Index 7:", str.charAt(7)); // Output: Character at Index 6: w

Q74. What is the output of the following code?

const str = "Node.js";
console.log(str.substring(2, -1));

1. Error
2. "No"
3. Undefined
4. "ode"

Q75. Which function is used to join an array of strings separated by a specific character in Node.js?

1. str.concat()
2. str.split()
3. str.join()
4. str.merge()

Q76. Which function is used to check if a string starts with a specified substring in Node.js?

1. str.startsWith()
2. str.substring()
3. str.contains()
4. str.firstIndexOf()

const str = "Hello, World!";
const substring = "Hello";

if (str.startsWith(substring)) {
    console.log("The string starts with the specified substring.");
} else {
    console.log("The string does not start with the specified substring.");
}

Q77. Which function is used to replace a specified substring with another string in Node.js?

1. str.replace()
2. str.replaceAll()
3. str.update()
4. str.modify()

Q78. What will be the output of the following code snippet?

const str = "Node.js Node.js";
console.log(str.indexOf("o", 0));  
console.log(str.lastIndexOf("o", 0));

1. 10 -1
2. 10 1
3. 1 0
4. 1 -1

const str = "Node.js Node.js";

console.log(str.indexOf("N"));         // Output: 0 (index of the first occurrence of "N" in the string)
console.log(str.lastIndexOf("N"));     // Output: 8 (index of the last occurrence of "N" in the string)
console.log(str.indexOf("n"));         // Output: -1 (no occurrence of lowercase "n" in the string)
console.log(str.lastIndexOf("n"));     // Output: -1 (no occurrence of lowercase "n" in the string)

console.log(str.indexOf("N", 1));      // Output: 8 (searching for "N" starting from index 1, finds it at index 8)
console.log(str.lastIndexOf("N", 1));  // Output: 0 (searching for "N" starting from index 1, finds it at index 0)

console.log(str.indexOf("N", 10));     // Output: -1 (no "N" found starting from index 10)
console.log(str.lastIndexOf("N", 10)); // Output: 8 (searching for "N" starting from index 10, finds it at index 8)

console.log(str.indexOf("Z", 1));      // Output: -1 ("Z" is not in the string)
console.log(str.lastIndexOf("Z"));     // Output: -1 ("Z" is not in the string)

Q79. What will be the output of the following JavaScript code snippet?

const str = "JavaScript";
console.log(str.slice(-4, -1));     // Output: ?
console.log(str.substring(-4, -1)); // Output: ?

1. Output: "scr", Output: "scr"
2. Output: "rip", Output: ""
3. Output: "rip", Output: "scr"
4. Output: "", Output: ""

const str = "JavaScript";
console.log(str.slice(2, 5));       // Output: "vaS"
console.log(str.substring(2, 5));   // Output: "vaS"
console.log(str.slice(2));          // Output: "vaScript" 
console.log(str.substring(2));      // Output: "vaScript" 
console.log(str.slice(-3));         // Output: "ipt" 
console.log(str.substring(-3));     // Output: "JavaScript"
console.log(str.slice(5, 2));       // Output: "" 
console.log(str.substring(5, 2));   // Output: "vaS"

Q80. Which function is used to convert a string to lowercase in Node.js?

1. str.toLowerCase()
2. str.toLower()
3. str.lowerCase()
4. str.convertToLower()

Q81. What is the output of the following code?

const str = "Node.js";
console.log(str.includes("node"));

1. true
2. false
3. Error
4. Undefined

Q82. What is the purpose of the "concat()" function in Node.js?

1. To split a string into an array
2. To match multiple strings
3. To join multiple strings together
4. To find the index of a specific character in a string

const str1 = "Hello";
const str2 = "Node.js";
const result = str1.concat(", ", str2);
console.log(result) // Hello, Node.js

Q83. What is the data type of numbers in Node.js?

1. Integer
2. Float
3. 64 bits floating point number
4. Double

const num1 = 10;
const num2 = 20.2;
console.log(`sum: ${num1 + num2}`); // sum: 30.2

Q84. Which functions are used to convert a string to a number in Node.js?

1. toNumber() and toInt()
2. int() and float()
3. parseInt() and parseFloat()
4. convertToInt() and convertToFloat()

console.log(parseInt("32"));  // 32
console.log(parseFloat("8.24")); // 8.24

Q85. What is the result of parseInt("234.12345")?

1. 234.12345
2. 234
3. NaN
4. 123.45

console.log(parseInt("234.12345")); // 234

Q86. What is the output of isFinite(10/5)?

1. true
2. false
3. 10
4. NaN

console.log(isFinite(10/5)); // true

Q87. What does the expression 5 / 0 return?

1. 0
2. Infinity
3. NaN
4. -Infinity

console.log(5 / 0); // Infinity
console.log(-5 / 0); // -Infinity

Q88. What is the primary advantage of using parseInt() over parseFloat()?

1. parseInt() always returns an integer.
2. parseFloat() is deprecated in Node.js.
3. parseInt() handles decimal values more accurately.
4. parseFloat() converts strings to numbers more efficiently.

console.log(parseInt("32"));  // 32

Q89. What does the function isFinite(10/0) return?

1. true
2. false
3. Infinity
4. NaN

console.log(isFinite(10/0)); // false

Q90. What is the purpose of the parseFloat() function?

1. To convert a string to an integer
2. To convert a string to a floating-point number
3. To check if a number is finite
4. To round a number to the nearest integer

console.log(parseFloat("8.24")); // 8.24

Q91. What is the output of parseInt("42px")?

1. 42
2. 42px
3. NaN
4. 0

console.log(parseInt("42px")); // 42

Q92. Which of the following functions can be used to check if a number is finite?

1. isFinite()
2. isNaN()
3. parseFloat()
4. parseInt()

console.log(isFinite(10/5)); // true

Q93. What is a BigInt value in Node.js?

1. A small integer
2. An integer followed by 'n'
3. A floating-point number
4. An integer with a decimal point

const maxSafeInteger = 99n;
console.log(maxSafeInteger); //99n

Q94. How to create a BigInt in Node.js using the BigInt() function?

1. By appending 'n' to an integer literal
2. By using the new operator with an integer value
3. By calling the BigInt() function with an integer or string value (without the new operator)
4. By using parseFloat() with a number

const num2 = BigInt('99'); // This is equivalent

Q95. What is the typeof a BigInt value in Node.js?

1. integer
2. float
3. bigint
4. string

let check=10n;
console.log(typeof(check)) //bigint

Q96. Which of the following is NOT a valid way to create a BigInt?

1. const num = 42n;
2. const num = BigInt(42);
3. const num = BigInt('42');
4. const num = 42.0n;

Q97. What is the purpose of using BigInts?

1. To represent floating-point numbers
2. To perform precise integer arithmetic beyond the limits of JavaScript's Number type
3. To create strings
4. To store boolean values

Q98. What are the possible values of the Boolean data type in Node.js?

1. true and false
2. 1 and 0
3. yes and no
4. string and number

const isValid = true;

Q99. Which function is used to convert any data type to a boolean value?

1. toBoolean()
2. bool()
3. Boolean()
4. convertToBoolean()

const n = 42;
const boolValue = Boolean(n);
console.log(boolValue) // true

Q100. Which of the following values evaluate to false when converted to a boolean?

1. true
2. 1
3. null
4. "false"

const boolValue = Boolean(null);

Q101. What is the result of the expression true && false?

1. true
2. false
3. null
4. undefined

console.log(false && false); // Output: false
console.log(false && true);  // Output: false
console.log(true && false);  // Output: false
console.log(true && true);   // Output: true

console.log(false || false); // Output: false
console.log(false || true);  // Output: true
console.log(true || false);  // Output: true
console.log(true || true);   // Output: true

Q102. What is the result of the expression !true in Node.js?

1. true
2. false
3. null
4. undefined

console.log(!true); // false

Q103. What is the value of `result` in the following code?

const isValid = false;
const result = isValid ? "Yes" : "No";

1. "Yes"
2. "No"
3. true
4. false

Q104. What is the result of the following expression?

const num1 = 42;
const num2 = 0;
const result = num1 && num2;

1. true
2. false
3. 0
4. 42

Q105. What is the typeof a BigInt value in Node.js?

const bigIntValue = 123n;

1. integer
2. float
3. bigint
4. string

Q106. What is the output of the following code?

const num = 42n;
console.log(num + 1n);

1. 43
2. 43n
3. 42n1
4. Error

Q107. What is the value of the variable "z" in the following code?

let z;
console.log(z);

1. Undefined
2. null
3. 0
4. NaN

Q108. What value does a variable take if it is assigned a null value?

1. 0
2. null
3. undefined
4. false

let y = null;
console.log(y); // null

Q109. What will be the output of the following code snippet?

let a = null;
let b = undefined;
console.log(typeof a === typeof b);

1. true
2. false
3. null
4. undefined

let a = null;
let b = undefined;
console.log(typeof a ); //object
console.log(typeof b ); //undefined
console.log(typeof a == typeof b); //false
console.log(typeof a === typeof b); //false

Q110. What does the following code snippet print?

let x = null;
let y = undefined;
console.log(x == y);

1. true
2. false
3. null
4. undefined

let x = null;
let y = undefined;
console.log(x === y); //false
console.log(x == y); //true
console.log(typeof x); //object
console.log(typeof y); //undefined

Q111. What is the purpose of the "Symbol" data type in Node.js?

1. To represent unique and immutable values
2. To create mutable variables
3. To store numeric values
4. To define functions

const NAME = Symbol();
const person = {
  [NAME]: 'India'
};
console.log(person[NAME]); // 'India'

Q112. What is a Symbol in Node.js?

1. A mutable primitive value
2. An immutable primitive value that is unique
3. An object with a private value
4. A string with special characters

const NAME = Symbol()

Q113. What is the main characteristic of a Symbol in Node.js?

1. It can be modified after creation
2. It is not unique and can have duplicate values
3. It is an object with public visibility
4. It is immutable and unique

Q114. How do you create a Symbol in Node.js?

1. Using curly braces
2. By defining a string
3. By calling the Symbol() function
4. By using special characters

const NAME = Symbol()

Q115. What is the purpose of a Symbol in Node.js?

1. To store public data
2. To represent special characters in strings
3. To create duplicate values
4. To create unique property keys for objects

// Creating a symbol
const mySymbol = Symbol("mySymbol");

// Creating an object with a symbol property
const myObject = {
  [mySymbol]: "This is a symbol property",
};

// Accessing the symbol property
console.log(myObject[mySymbol]); // Output: 'This is a symbol property'

Q116. How does Node.js contribute to processing efficiency?

1. By using a multi-threaded model
2. By processing events one after another
3. By waiting for blocking IO operations before continuing
4. By following a Request/Response Multi-Threaded Stateless Model

Q117. Primary role of Event Loop

1. To handle blocking IO operations
2. To manage the Thread Pool
3. To process client requests in a multi-threaded manner
4. To receive and process client requests in a single-threaded, event-driven loop

Q118. When does a Thread from the Internal Thread Pool get involved in Node.js processing model?

1. For every client request
2. Only for requests involving blocking IO operations
3. When processing client requests concurrently
4. When waiting for the Event Queue to be populated

Q119. How does Node.js handle blocking IO operations in its processing model?

1. Main Event Loop processes blocking IO operations
2. Separate thread for each blocking IO operation
3. Blocking IO requests in a separate Event Queue
4. Dedicated thread from Internal Thread Pool for each blocking IO operation

Q120. How does Node.js differ from a Request/Response Multi-Threaded Stateless Model?

1. Uses multiple threads for processing client requests
2. Follows a single-threaded model with an Event Loop
3. Processes each request in a blocking manner
4. Relies on a traditional multi-threaded approach

Q121. Purpose of the Limited Thread Pool

1. Process client requests concurrently
2. Handle blocking IO operations
3. Manage the Event Loop
4. Serve as the main processing unit for Node.js

Q122. How does Node.js manage asynchronous operations?

1. Using callbacks and Promises
2. Executing operations sequentially
3. Blocking the Event Loop for each operation
4. Assigning a separate thread for each operation

Q123. Role of Node.js Event Loop in Concurrent Connections

1. Creating a new thread for each connection
2. Managing connections in a separate Event Queue
3. Utilizing a single thread for all connections
4. Blocking the Event Loop for each connection