Salesforce Javascript Developer 1 Practice Exam Questions and Answers 2024

Mastering Salesforce development opens doors to exciting career opportunities.  From designing and implementing custom solutions to integrating third-party apps and optimizing workflows, Salesforce developers play a pivotal role in driving innovation and efficiency for businesses worldwide.  

In this blog, we’ve compiled a curated selection of SF JS Developer 1 exam questions and their detailed answers, covering essential topics and concepts you’ll encounter on the Salesforce JavaScript Developer I exam. From data types and operators to DOM manipulation and event handling, we’ve got you covered.

Salesforce Javascript Developer 1 Practice Exam Questions and Answers 2024

1. Which of the following is NOT a valid data type in JavaScript?

a) String

b) Integer

c) Decimal

d) Blob 

Answer: d) Blob

Explanation: Blob is not a native JavaScript data type. It’s used in Salesforce to represent binary data.

2. What is the purpose of the event.preventDefault() method in a JavaScript event handler?

a) To define a new event

b) To cancel the default behavior of an event  

c) To access event data

d) To trigger another event

Answer: b) To cancel the default behavior of an event  

Explanation: This method prevents the browser’s default action associated with an event, allowing for custom behavior in your code.

3. How can you iterate over the elements of an array in JavaScript?

a) Using a for loop  

b) Using a while loop

c) Using the each method (not standard JavaScript)

d) There’s no built-in way to iterate over arrays

Answer: a) Using a for loop  

Explanation: The for loop is the standard way to iterate over each element in an array.

4. What is the syntax for defining a function in JavaScript?

a) function name(parameters) { code } 

b) define function name(parameters) { code }

c) var function name(parameters) { code }

d) createFunction name(parameters) { code }

Answer: a) function name(parameters) { code }

Explanation: The provided syntax is the correct way to define a function in JavaScript.

5. How do you access the value of a Visualforce variable within a JavaScript controller?

a) Directly using the variable name

b) Using the {!varName} syntax 

c) Using the $Component.getVariable(“varName”) method

d) Visualforce variables are not accessible in JavaScript controllers

Answer: b) Using the {!varName} syntax

Explanation: The {!varName} syntax allows you to access Visualforce variables within JavaScript controllers.

6. What is the difference between == and === operators in JavaScript?

a) There’s no difference, they both compare for equality

b) == performs loose comparison, === performs strict comparison  

c) == is used for assignment, === is used for comparison

d) == compares values, === compares values and types

Answer: b) == performs loose comparison, === performs strict comparison

Explanation: == performs loose comparison, which may convert data types before comparison. === performs strict comparison, ensuring both value and data type are identical.

7. How can you trigger a Lightning component event from a JavaScript controller?

a) Using the fireEvent method on the component object

b) By calling the event handler directly 

c) Using a custom JavaScript function

d) Events cannot be triggered from controllers

Answer: b) By calling the event handler directly

Explanation: You can trigger a Lightning component event from a controller by calling the event handler function directly.

8. What is the purpose of the Apex.execute method in JavaScript?

a) To perform server-side calculations

b) To call Apex methods from JavaScript 

c) To access Salesforce data

d) To manipulate DOM elements

Answer: b) To call Apex methods from JavaScript

Explanation: The Apex.execute method allows asynchronous calls to Apex methods from JavaScript controllers.

9. What is the Lightning Data Service (LDS) used for?

a) To manage user interface components

b) To interact with Salesforce data  

c) To handle client-side routing

d) To perform complex calculations

Answer: b) To interact with Salesforce data

Explanation: LDS provides a framework for interacting with Salesforce data from Lightning components.

10. How can you deep clone an object in JavaScript to create a completely new copy that doesn’t modify the original?

a) By simply assigning the object to a new variable (creates a shallow copy)

b) There’s no built-in way to deep clone objects

c) Using a custom function that iterates through the object and its properties  

d) Using libraries like lodash for object manipulation

Answer: c) Using a custom function that iterates through the object and its properties

Explanation: To create a completely independent copy (deep clone), you need a custom function that iterates through the object and its nested properties, creating new copies for each level.

Also Read – Salesforce JavaScript Developer 1 Exam Guide

11. What is the difference between alert, confirm, and prompt methods in JavaScript?

a) All display messages, but prompt allows user input  

b) alert displays a message, confirm asks a yes/no question, prompt doesn’t exist

c)  They all perform the same action

d) alert displays an error, confirm displays a warning, prompt displays information

Answer: a) All display messages, but prompt allows user input 

Explanation: All three display messages, but prompt allows the user to enter text input.

12. How can you prevent a variable from being accidentally reassigned in JavaScript?

a) By declaring it with let instead of var

b) By prefixing the variable name with an underscore

c) There’s no way to prevent reassignment

d) Using the const keyword 

Answer: d) Using the const keyword

Explanation: The const keyword declares a variable that cannot be reassigned after its initial value is set.

13. What is the purpose of the window.location object in JavaScript?

a) To manipulate browser history

b) To access and modify the current URL  

c) To manage browser window size and position

d) To interact with browser cookies

Answer: b) To access and modify the current URL

Explanation: The window.location object provides properties and methods for getting and modifying the current URL.

14. How can you sort an array of objects based on a specific property in JavaScript?

a) Using a custom sorting function with the sort method  

b) There’s no built-in way to sort objects in arrays

c) Using a separate loop to iterate and sort

d) Using the orderBy method (not standard JavaScript)

Answer: a) Using a custom sorting function with the sort method

Explanation: The sort method can be used with a custom function to compare objects based on specific properties.

15. What is the difference between synchronous and asynchronous code execution in JavaScript?

a) Synchronous code waits for tasks to finish before continuing, asynchronous doesn’t wait  

b) Synchronous code deals with numbers, asynchronous code deals with strings

c) Synchronous code is faster, asynchronous code is slower

d) There’s no practical difference

Answer: a) Synchronous code waits for tasks to finish before continuing, asynchronous doesn’t wait

Explanation: Synchronous code executes line by line, waiting for one task to finish before moving on. Asynchronous code allows other tasks to run concurrently without blocking the main thread.

16. How can you debounce a function call in JavaScript?

a) By wrapping the function in a setTimeout call

b) By using a custom function that tracks the last call time  

c) There’s no built-in way to debounce functions

d) Debouncing is not relevant in JavaScript

Answer: b) By using a custom function that tracks the last call time

Explanation: Debouncing ensures a function doesn’t execute multiple times in rapid succession. You can achieve this with a custom function that tracks the last call time and delays subsequent calls until a certain time has passed.

17. What is ‘this’ keyword in JavaScript and how does it work within event handlers?

a) this refers to the window object by default

b) this refers to the element the event handler is attached to  

c) this is undefined within event handlers

d) this refers to the function itself

Answer: b) this refers to the element the event handler is attached to

Explanation: Within event handlers, ‘this’ keyword typically refers to the DOM element that triggered the event.

18. How can you chain method calls in JavaScript?

a) By using separate variables for each method call

b) By calling methods one after another on the same object 

c) Chaining is not possible in JavaScript

d) Using a loop to iterate through methods

Answer: b) By calling methods one after another on the same object

Explanation: Chaining allows you to call multiple methods on the same object sequentially, improving code readability.

19. What is the difference between GET and POST HTTP methods?

a) GET retrieves data, POST submits data  

b) GET is faster, POST is slower

c) GET is more secure, POST is less secure

d) There’s no functional difference

Answer: a) GET retrieves data, POST submits data

Explanation: GET requests are used to retrieve data from a server, while POST requests are used to submit data to a server.

20. What is the purpose of the console.log method in JavaScript?

a) To display debug messages in the browser developer console  

b) To write data to a server-side log file

c) To create pop-up messages for users

d) To interact with browser cookies

Answer: a) To display debug messages in the browser developer console

Explanation: The console.log method is a debugging tool that allows you to output messages to the browser’s developer console. This is helpful for inspecting variables, logging code execution flow, and identifying errors during development.

21. How can you check if a variable is an array in JavaScript?

a) Using the isArray method  

b) By checking the variable type with typeof and comparing to “array”

c) There’s no built-in way to check for arrays

d) Using a loop to iterate through the variable

Answer: a) Using the isArray method

Explanation: The Array.isArray(variable) method definitively checks if a variable is an array.

22. What is the purpose of the for…of loop in JavaScript?

a) To iterate over the keys of an object

b) To iterate over the values of an iterable object 

c) Similar to a for loop, but for strings only

d) There’s no practical difference between for and for…of loops

Answer: b) To iterate over the values of an iterable object

Explanation: The for…of loop is specifically designed to iterate over the values of iterable objects like arrays and strings.

23. How can you implement error handling using a try…catch block in JavaScript?

a) By wrapping the code that might throw errors in a try block and defining error handling in a catch block 

b) Using an if statement to check for errors

c) There’s no built-in way to handle errors in JavaScript

d) Errors automatically display an alert message

Answer: a) By wrapping the code that might throw errors in a try block and defining error handling in a catch block 

Explanation: try…catch blocks allow you to define code that might throw errors within the try block and handle those errors gracefully using the catch block.

24. What is the difference between primitive data types and reference data types in JavaScript?

a) Primitive data types are stored by reference, reference data types are stored by value  

b) Primitive data types are simple values, reference data types hold complex data structures

c) There’s no meaningful difference

d) Primitive data types are slower to access

Answer: a) Primitive data types are stored by reference, reference data types are stored by value

Explanation: Primitive data types (like numbers, strings) hold the actual value. Reference data types (like objects, arrays) store a reference to the memory location where the actual data resides.

25. How can you iterate over the properties of an object in JavaScript?

a) Using a for loop with the object name

b) Using the Object.keys method to get an array of keys and then looping through them  

c) There’s no built-in way to iterate over object properties

d) Using a for…of loop (not recommended for objects)

Answer: b) Using the Object.keys method to get an array of keys and then looping through them

Explanation: The Object.keys method returns an array of an object’s property names, which you can then use to iterate through the properties.

26. What is the document.querySelector method used for in JavaScript?

a) To select the first element matching a CSS selector 

b) To select all elements matching a CSS selector

c) To manipulate the DOM structure

d) To add event listeners to elements

Answer: a) To select the first element matching a CSS selector

Explanation: document.querySelector selects the first element that matches a specified CSS selector within the document.

27. How can you prevent default form submission behavior in JavaScript?

a) By modifying the form element’s action attribute

b) By calling the preventDefault method on the event object within the form’s submit event handler  

c) There’s no way to prevent default form submission

d) Using a confirmation dialog before form submission

Answer: b) By calling the preventDefault method on the event object within the form’s submit event handler

Explanation: Calling preventDefault on the event object within the form’s submit event handler stops the browser’s default form submission behavior.

28. What is the purpose of the window.addEventListener method in JavaScript?

a) To attach an event listener to a DOM element 

b) To trigger a specific DOM event

c) To access information about the current window

d) To manipulate browser window dimensions

Answer: a) To attach an event listener to a DOM element

Explanation: window.addEventListener allows you to attach an event listener to a DOM element, defining a function to execute when that event occurs.

29. What is the DOM (Document Object Model) in JavaScript and how is it used?

a) A database for storing web page content

b) A representation of an HTML document as a tree structure, allowing manipulation of web page content  

c) A way to style web pages using CSS

d) A method for fetching data from external APIs

Answer: b) A representation of an HTML document as a tree structure, allowing manipulation of web page content

Explanation: The DOM is a programming interface that represents an HTML document as a tree of objects. This structure allows JavaScript to access, modify, and interact with the various elements and content of the web page.

30. How can you create a custom JavaScript module and export functions or variables for use in other parts of your code?

a) Using a defineModule function (not standard JavaScript)

b) There’s no built-in way to create modules in JavaScript 

c) By creating a separate JavaScript file and including it in your HTML

d) Using IIFEs (Immediately Invoked Function Expressions)

Answer: c) By creating a separate JavaScript file and including it in your HTML 

Explanation: This is the standard approach for creating modules in JavaScript. You can define functions and variables within the separate JavaScript file and then use export statements to make them accessible for use in other parts of your code by including the file in your HTML using a <script> tag.

Additional Resources and Tips

Conquering the Salesforce JavaScript Developer 1 exam requires dedication and a solid understanding of the core concepts. Here are some additional resources and tips to help you ace your exam:

Salesforce JavaScript Developer 1 Study Guide

This official guide outlines the exam objectives and provides valuable learning resources. Make sure you thoroughly study the content covered in this guide.

Salesforce Trailhead Modules

Trailhead offers a variety of free modules specifically designed to prepare you for the exam. These interactive modules cover key topics with hands-on exercises to solidify your understanding.

Salesforce Developer Documentation

The official documentation serves as a comprehensive reference for all things Salesforce development, including JavaScript. Utilize this resource to explore specific topics or syntax in detail.

Coding Challenges

Challenge yourself by participating in online coding challenges or exercises focused on Salesforce JavaScript development. Platforms like HackerRank or LeetCode offer practice problems designed to test your problem-solving skills and coding abilities.

Personal Projects

Building your own Salesforce projects using JavaScript is a fantastic way to apply your knowledge in a practical setting. This hands-on experience not only reinforces your understanding but also allows you to showcase your skills on a portfolio.

Conclusion

By mastering the intricacies of Salesforce’s robust ecosystem, developers can unlock doors to innovation, efficiency, and professional growth. Salesforce development presents a pathway filled with potential and possibilities. So, seize the opportunity, take on the challenge, and set out on a rewarding journey towards becoming a proficient Salesforce developer. 

Ready to transform your Salesforce expertise? Sign up for saasguru’s free trial today! Gain access to over 24 Salesforce Certification Courses, including the Salesforce JavaScript Developer 1 Course, 50+ Mock Exams, and 50+ Salesforce Labs for hands-on learning. 

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Frequently Asked Questions (FAQs)

1. How to prepare for JavaScript Developer 1?

• Review Salesforce Documentation:  Salesforce provides comprehensive documentation and learning resources specifically for the JavaScript Developer 1 exam. 
• Take Practice Tests: Utilize practice tests to assess your knowledge and identify areas needing improvement. 
• Enroll in Online Courses: Consider enrolling in online courses or attending bootcamps focused on Salesforce JavaScript development.
• Build Projects:  Hands-on experience is invaluable. Work on personal or sample projects to solidify your understanding of concepts.
• Join the Salesforce Community: Engage with the Salesforce developer community through forums and discussions to learn from others.

2. What is the pass percentage for Salesforce Developer 1 certification?

The pass percentage for Salesforce Developer 1 certification is 65%

3. How many questions are there in Salesforce Platform Developer 1?

The current iteration of the exam (Salesforce JavaScript Developer 1) consists of 60 multiple-choice/multiple-select questions.

4. Is the Salesforce Developer exam hard?

The difficulty depends on your experience level with JavaScript and Salesforce development. With proper preparation, the exam is achievable.