JSA-41-01 Dumps (V8.02) with JSA-41-01 Free Dumps (Part 2, Q41-Q90) – Increase Your Score in the Actual JSA – Certified Associate JavaScript Programmer Exam

1. Given the following JavaScript code snippet, what will be logged to the console?

1. let myMap = new Map();

2. myMap.set('key1', 'value1');

3. myMap.set('key2', 'value2');

4. myMap.set('key1', 'updatedValue');

5.

6. console.log(myMap.get('key1'));

7. console.log(myMap.size);

2. In JavaScript, you can copy objects using various methods.

Which of the following functions correctly creates a deep copy of a given object?

3. Given the following code snippet, what will be the output?

1. let str1 = new String("apple");

2. let str2 = new String("Apple");

3. let result = str1 == str2;

4. console.log(result);

4. You need to load multiple resources for a dashboard, and each resource fetch depends on the result of the previous fetch. You decide to use async and await to ensure each fetch is completed before the next one starts.

1. async function loadDashboardData() {

2. try {

3. const chartData = await loadChartData();

4. const userData = await loadUserData(chartData);

5. const notificationData = await loadNotificationData(userData);

6. console.log('Dashboard data loaded successfully:', {

10. });

11. } catch (error) {

12. console.error('Error loading dashboard data:', error);

13. }

14. }

What is the primary reason for using async and await in this scenario?

5. Consider the following code snippet in JavaScript:

1. class Library {

2. constructor() {

3. this.books = [];

4. }

5.

6. addBook(book) {

7. this.books.push(book);

8. }

9.

10. get totalBooks() {

11. return this.books.length;

12. }

13.

14. removeBook(title) {

15. this.books = this.books.filter(book => book.title !== title);

16. }

17. }

18.

19. const library = new Library();

20. library.addBook({ title: 'Book A', author: 'Author A' });

21. library.addBook({ title: 'Book B', author: 'Author B' });

22. library.addBook({ title: 'Book C', author: 'Author C' });

23. library.removeBook('Book B');

24. console.log(library.totalBooks);

What will be the output of the console.log(library.totalBooks) statement?

6. Consider the following JavaScript code snippet.

Which two statements about the code are correct?

1. class Product {

2. constructor(name, price) {

3. this.name = name;

4. this.price = price;

5. }

6.

7. discount(amount) {

8. return this.price - amount;

9. }

10. }

11.

12. const product = new Product('Laptop', 1000);

13. console.log(product.discount(100));

7. You have an array of task objects, each with a description and a completed status. You need to filter out the completed tasks and then create a new array that contains only the descriptions of the incomplete tasks.

Which of the following code snippets correctly implements this logic using the spread operator?

1. const tasks = [{

2. description: 'Task 1',

3. completed: true

4. },

5. {

6. description: 'Task 2',

7. completed: false

8. },

9. {

10. description: 'Task 3',

11. completed: true

12. },

13. {

14. description: 'Task 4',

15. completed: false

16. }

17. ];

18.

19. const incompleteTasks = tasks.filter(task => !task.completed);

20. const descriptions = [...incompleteTasks.map(task => task.description)];

21. console.log(descriptions);

8. What will be the output of the following code?

1. var result = (function() {

2. var name = "John Doe";

3. return name;

4. })();

5.

6. console.log(result);

9. Consider the following code snippet:

1. let name = "John Doe";

2. let upperName = new String(name.toUpperCase());

3. let finalName = upperName.toLowerCase().slice(0, 4);

4. console.log(finalName);

What will be the output?

10. You need to manage a Map of user IDs and their login statuses in a web application.

Given the following code snippet, what will be the state of the logins map after all operations?

1. let logins = new Map([

2. [201, 'online'],

3. [202, 'offline'],

4. [203, 'online']

5. ]);

6.

7. logins.set(204, 'offline');

8. logins.set(202, 'online');

9. logins.delete(203);

10. logins.set(201, 'offline');

11.

12. let onlineUsers = [];

13. for (let [id, status] of logins) {

14. if (status === 'online') {

15. onlineUsers.push(id);

16. }

17. }

Which array will onlineUsers contain?

11. Why is using JSON.parse(JSON.stringify(object)) not always suitable for deep cloning objects?

12. Consider the following JavaScript code:

1. class Library {

2. static totalBooks = 0;

3.

4. constructor(name, books) {

5. this.name = name;

6. this.books = books;

7. Library.addBooks(books);

8. }

9.

10. static addBooks(number) {

11. Library.totalBooks += number;

12. }

13. }

14.

15. let library1 = new Library('Central Library', 500);

16. let library2 = new Library('Westside Library', 300);

17. let library3 = new Library('Eastside Library', 200);

18.

19. console.log(Library.totalBooks);

What will be the output of console.log(Library.totalBooks) ?

13. Given the following code snippet, what will be the output when myCar.getDetails() is called?

1. const Car = class {

2. constructor(make, model) {

3. this.make = make;

4. this.model = model;

5. }

6.

7. getDetails() {

8. console.log(`Car make: ${this.make}, Model: ${this.model}`);

9. }

10. };

11.

12. const myCar = new Car('Toyota', 'Camry');

13. myCar.getDetails();

14. You are tasked with developing a custom iterator to traverse a deeply nested object structure, ensuring that each value is processed without using recursion to avoid stack overflow errors.

Which of the following implementations would be the most appropriate?

15. You have an object representing a book and you want to create a copy of this object while updating the price property.

Which code snippet correctly creates the updated copy using the spread operator?

1. const book = {

2. title: 'JavaScript Essentials',

3. author: 'John Doe',

4. price: 20

5. };

6.

7. const updatedBook = __________;

8.

9. console.log(updatedBook);

16. Which of the following statements correctly demonstrates testing for the presence of a field in a JavaScript object using the in keyword?

17. What is the primary purpose of the__proto__property in JavaScript objects?

18. Which of the following statements correctly compares dot notation and bracket notation in JavaScript, with an emphasis on dot notation as the primary way to refer to object fields?

19. Which of the following is NOT a valid way to create a classless object in JavaScript?

20. You have an array of numbers that you want to pass as individual arguments to a function that calculates their product.

Which implementation correctly achieves this using the spread operator?

21. Given the following code snippet, which of the following options will correctly test if the string "hello123" contains one or more digits?

1. let str = "hello123";

2. let regex = /[0-9]+/;

22. You need to create a JavaScript function createMultiplier that takes a number factor and returns a new function that multiplies its argument by factor.

Which of the following implementations correctly achieves this?

23. Given the following code snippet, which two statements about the output are correct?

1. class Animal {

2. constructor(name) {

3. this.name = name;

4. }

5.

6. speak() {

7. console.log(`${this.name} makes a noise.`);

8. }

9. }

10.

11. class Dog extends Animal {

12. speak() {

13. console.log(`${this.name} barks.`);

14. }

15. }

16.

17. const myDog = new Dog('Rex');

18. myDog.speak();

24. Consider the following JavaScript code snippet.

What will be the output of the displayDetails function when it is called?

1. const user = {

2. firstName: "John",

3. lastName: "Doe",

4. getFullName: function() {

5. return this.firstName + " " + this.lastName;

6. }

7. };

8.

9. const displayDetails = function() {

10. return user.getFullName();

11. };

12.

13. console.log(displayDetails());

25. Given the following object and scenario:

1. var person = {

2. name: "Alice",

3. age: 30,

4. greet: function() {

5. return "Hello, " + this.name;

6. }

7. };

Which method correctly calls the greet function and alerts the greeting?

26. You have an object vehicle and want to create another object car that inherits properties from vehicle using the __proto__ property.

Which of the following code snippets correctly sets up this inheritance?

1. let vehicle = {

2. type: 'Vehicle',

3. move: function() {

4. return 'Moving';

5. }

6. };

27. Consider the following JavaScript object:

1. let person = {

2. name: "Alice",

3. age: 25,

4. occupation: "developer"

5. };

Which two of the following statements correctly check for property existence or enumerate the properties of the person object?

28. You are developing a feature that requires you to chain multiple asynchronous operations.

Given a function getUserProfile that fetches a user's profile and a function getPosts

that fetches posts for a user, you need to:

1. Fetch the user profile.

2. Fetch the posts of that user based on the profile data.

3. Log both the profile and posts data if both operations succeed.

4. Log an error message if any of the operations fail.

5. Log a message "Process finished" after both operations are complete, regardless of success or failure.

Which code snippet correctly achieves this?

29. JavaScript supports classless objects where objects are created directly from prototypes.

Which of the following statements correctly describes the behavior of classless objects compared to class-based objects?

30. You are tasked with managing a set of unique product IDs in an e-commerce application. You need to add new product IDs, check for their existence, and remove some of them based on certain conditions.

Given the following code snippet, what will be the output?

1. let productIDs = new Set();

2. productIDs.add(101).add(102).add(103).add(101);

3. productIDs.delete(102);

4. productIDs.add(104);

5.

6. if (productIDs.has(103)) {

7. productIDs.delete(103);

8. }

9. console.log(productIDs.size);

What will the console.log statement print?

31. You need to find the minimum and maximum values in an array of numbers and then calculate the difference between the ceiling of the minimum value and the floor of the maximum value.

Which of the following implementations is correct?

1. function minMaxDifference(arr) {

2. // code here

3. }

32. Given the following class definition, what will be the output of the code?

1. class Animal {

2. type = 'mammal';

3.

4. constructor(name) {

5. this.name = name;

6. }

7.

8. describe() {

9. return `${this.name} is a ${this.type}`;

10. }

11.

12. setType(newType) {

13. this.type = newType;

14. }

15. }

16.

17. const animal = new Animal("Elephant");

18. animal.setType("herbivore");

19. console.log(animal.describe());

33. Consider the following implementation of an iterator:

1. const myIterable = {

2. [Symbol.iterator]: function() {

3. let step = 0;

4. return {

13. };

14. }

15. };

16.

17. const iterator = myIterable[Symbol.iterator]();

18. console.log(iterator.next().value); // ?

19. console.log(iterator.next().value); // ?

20. console.log(iterator.next().value); // ?

21. console.log(iterator.next().value); // ?

What will be the output of the above code?

34. Which of the following methods correctly rounds the number 4.56789 to two decimal places in JavaScript?

35. Consider the following JavaScript code:

1. class Employee {

2. constructor(name) {

3. this.name = name;

4. }

5. getDetails() {

6. return `Employee Name: ${this.name}`;

7. }

8. }

9.

10. class Manager extends Employee {

11. constructor(name, department) {

12. super(name);

13. this.department = department;

14. }

15. getDetails() {

16. return `Manager Name: ${this.name}, Department: ${this.department}`;

17. }

18. }

19.

20. let manager = new Manager('Alice', 'HR');

21. console.log(manager.getDetails());

What will be the output of console.log(manager.getDetails())?

36. Which of the following best describes how to create a classless object that includes methods in JavaScript?

37. Which of the following statements correctly demonstrates how to add a key-value pair to a Map object, and how to retrieve a value using the key?

38. You want to add a method first to the Array prototype that returns the first element of the array.

Which of the following code snippets correctly achieves this?

39. You are developing a dictionary-type data structure in JavaScript to store information about various countries, where the key is the country code and the value is an object containing the country's name and population.

Which code snippet correctly implements adding a new country to the dictionary?

1. const countries = {

2. USA: {

3. name: 'United States',

4. population: 331000000

5. },

6. CAN: {

7. name: 'Canada',

8. population: 37700000

9. },

10. MEX: {

11. name: 'Mexico',

12. population: 128000000

13. }

14. };

15.

16. // Add a new country - Germany (code: GER, name: 'Germany', population: 83000000)

17. __________

18.

19. console.log(countries.GER);

40. You need to create a classless object that inherits from another object. Given the base object animal, which code snippet correctly creates a new object dog that inherits properties from animal?

1. let animal = {

2. species: 'Animal',

3. sound: function() {

4. return 'Some sound';

5. }

6. };

41. Which of the following regular expressions will correctly validate if the given string "A1b2C3" follows the pattern of alternating letters and digits?

42. Given the following class definition, what will be the output of the code?

1. class Book {

2. constructor(title, author) {

3. this._title = title;

4. this._author = author;

5. }

6.

7. get title() {

8. return this._title;

9. }

10.

11. set title(newTitle) {

12. this._title = newTitle;

13. }

14.

15. get author() {

16. return this._author;

17. }

18.

19. set author(newAuthor) {

20. this._author = newAuthor;

21. }

22.

23. getDetails() {

24. return `${this.title} by ${this.author}`;

25. }

26. }

27.

28. const myBook = new Book("1984", "George Orwell");

29. myBook.title = "Animal Farm";

30. console.log(myBook.getDetails());

43. You need to implement a function to update the population of a specific country in your dictionary-type data structure.

Which function implementation correctly updates the population?

1. const countries = {

2. USA: {

3. name: 'United States',

4. population: 331000000

5. },

6. CAN: {

7. name: 'Canada',

8. population: 37700000

9. },

10. MEX: {

11. name: 'Mexico',

12. population: 128000000

13. }

14. };

15.

16. function updatePopulation(countryCode, newPopulation) {

17. __________

18. }

19.

20. updatePopulation('CAN', 38000000);

21. console.log(countries.CAN.population);

44. Consider the following JavaScript code:

1. class Vehicle {

2. constructor(make, model) {

3. this.make = make;

4. this.model = model;

5. }

6. }

7.

8. class Car extends Vehicle {

9. constructor(make, model, year) {

10. super(make, model);

11. this.year = year;

12. }

13. }

14.

15. let myCar = new Car('Toyota', 'Corolla', 2020);

16. console.log(myCar);

What will be the output of console.log(myCar)?

45. Which of the following code snippets correctly demonstrates creating a new array by merging two arrays using the spread operator, and then adding a new element to the beginning of the merged array?

46. Which of the following correctly generates a random integer between 1 and 10 (inclusive)?

47. You have the following JavaScript code:

1. function createCounter() {

2. let count = 0;

3. return {

4. increment: function() {

7. },

8. decrement: function() {

11. }

12. };

13. }

14.

15. const counter = createCounter();

16. console.log(counter.increment()); // Output?

17. console.log(counter.decrement()); // Output?

18. console.log(counter.increment()); // Output?

What will be the output of the above code when it is executed?

48. Consider the following code snippet:

1. const myObject = {

2. data: [10, 20, 30],

3. [Symbol.iterator]: function() {

4. let index = 0;

5. const self = this;

6. return {

14. };

15. }

16. };

17.

18. const iterator = myObject[Symbol.iterator]();

19. console.log(iterator.next().value); // ?

20. console.log(iterator.next().value); // ?

21. console.log(iterator.next().value); // ?

22. console.log(iterator.next().value); // ?

What will be the output of the above code?

49. You are working on a web application that fetches user data from a remote server using the Fetch API. You need to handle the response correctly to update the UI with the user's information.

What is the correct way to handle the asynchronous fetch request to ensure that the user data is correctly processed and displayed?

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

1. let a = new Number(5);

2. let b = 5;

3. console.log(a == b, a === b);