JavaScript Online Test

Q: What are the main Front End developer tests?

Here are some important Front End developer tests: JavaScript Online Test Angular Online Test React.js Online Test Vue.js Test

The JavaScript test uses scenario-based MCQs to evaluate candidates on JavaScript fundamentals (ES5, ES6), ability to manipulate HTML DOM and Asynchronous programming with Ajax, Fetch API, Promises & Async / Await. The test includes coding questions to evaluate hands-on JavaScript programming skills.

Covered skills:

JavaScript basics (arrays; objects; strings; functions)
Structuring and styling HTML DOM
Errors and Exception Handling
Working with user data and JSON
ES6 (arrow functions; destructuring; spreads)
higher-order functions and closures
OOP (classes; constructors; prototypal inheritance)
Asynchronous JavaScript (event loop; promises; async/await)
Handling APIs

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About the JavaScript Test

The JavaScript Online Test helps recruiters and hiring managers identify qualified candidates from a pool of resumes, and helps in taking objective hiring decisions. It reduces the administrative overhead of interviewing too many candidates and saves time by filtering out unqualified candidates at the first step of the hiring process.

The test screens for the following skills that hiring managers look for in candidates:

Proficient in JavaScript basics including arrays, objects, strings, and functions
Knowledge of structuring and styling HTML DOM
Ability to handle exceptions and errors efficiently
Experience in working with user data and JSON
Familiarity with ES6 features such as arrow functions, destructuring, and spreads
Understanding of higher-order functions and closures
Competence in OOP concepts including classes, constructors, and prototypal inheritance
Capability to work with Asynchronous JavaScript using event loop, promises, and async/await
Skill in handling APIs

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Non-googleable questions

We have a very high focus on the quality of questions that test for on-the-job skills. Every question is non-googleable and we have a very high bar for the level of subject matter experts we onboard to create these questions. We have crawlers to check if any of the questions are leaked online. If/ when a question gets leaked, we get an alert. We change the question for you & let you know.

How we design questions

These are just a small sample from our library of 15,000+ questions. The actual questions on this JavaScript Online Test will be non-googleable.

🧐 Question
Medium Async Await Promises Promises Async-Await Asynchronous Programming	Solve
What will the following code output? A: 24 after 5 seconds and after another 5 seconds, another 24 B: 24 followed by another 24 immediately C: 24 immediately and another 24 after 5 seconds D: After 5 seconds, 24 and 24 E: Undefined F: NaN G: None of these
Medium Bitcoin prices Axios Promises	Solve
Review the following JavaScript code and pick the correct options: Assume that the API returns a successful 200 response code and a JSON object as the response body. What would the value of ‘a’ be after the code is executed?
Medium My Module Scope Javascript Es6 Closure	Solve
What will the output of the following JavaScript code be?
Medium Promise Resolve Promises Async-Await Code Analysis Syntax Understanding	Solve
What does the following code output?
Easy Throw, Try, Async Promises Async-Await Async/await	Solve
What does the following JS code output?
Easy Registration Queue Logic Queues Sorting By Custom Order	Solve
We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount. For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition. ⚠️⚠️⚠️ Note: - The first line of the input is the length of the array. The second line contains all the elements of the array. - The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function. - You need to "print" the final result (not return it) to pass the test cases. For the example discussed above, the input will be: 5 20 70 -40 30 -10 Your code needs to print the following to the standard output: 20 70 30 -40 -10
Medium Visitors Count Strings Logic String Parsing Character Counting	Solve
A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. Example: Input: WWMMWWCCC Expected Output: 4W3C2M Explanation: ‘W’ has the highest count, then ‘C’, then ‘M’. ⚠️⚠️⚠️ Note: - The input is already parsed and passed to a function. - You need to "print" the final result (not return it) to pass the test cases. - If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’. - If any of them have the same count, the output should follow this order - M, W, C.

	🧐 Question	🔧 Skill
	Medium Async Await Promises Promises Async-Await Asynchronous Programming	2 mins JavaScript	Solve
What will the following code output? A: 24 after 5 seconds and after another 5 seconds, another 24 B: 24 followed by another 24 immediately C: 24 immediately and another 24 after 5 seconds D: After 5 seconds, 24 and 24 E: Undefined F: NaN G: None of these
	Medium Bitcoin prices Axios Promises	2 mins JavaScript	Solve
Review the following JavaScript code and pick the correct options: Assume that the API returns a successful 200 response code and a JSON object as the response body. What would the value of ‘a’ be after the code is executed?
	Medium My Module Scope Javascript Es6 Closure	2 mins JavaScript	Solve
What will the output of the following JavaScript code be?
	Medium Promise Resolve Promises Async-Await Code Analysis Syntax Understanding	2 mins JavaScript	Solve
What does the following code output?
	Easy Throw, Try, Async Promises Async-Await Async/await	2 mins JavaScript	Solve
What does the following JS code output?
	Easy Registration Queue Logic Queues Sorting By Custom Order	30 mins Coding	Solve
We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount. For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition. ⚠️⚠️⚠️ Note: - The first line of the input is the length of the array. The second line contains all the elements of the array. - The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function. - You need to "print" the final result (not return it) to pass the test cases. For the example discussed above, the input will be: 5 20 70 -40 30 -10 Your code needs to print the following to the standard output: 20 70 30 -40 -10
	Medium Visitors Count Strings Logic String Parsing Character Counting	30 mins Coding	Solve
A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. Example: Input: WWMMWWCCC Expected Output: 4W3C2M Explanation: ‘W’ has the highest count, then ‘C’, then ‘M’. ⚠️⚠️⚠️ Note: - The input is already parsed and passed to a function. - You need to "print" the final result (not return it) to pass the test cases. - If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’. - If any of them have the same count, the output should follow this order - M, W, C.

	🧐 Question	🔧 Skill	💪 Difficulty	⌛ Time
	Async Await Promises Promises Async-Await Asynchronous Programming	JavaScript	Medium	2 mins	Solve
What will the following code output? A: 24 after 5 seconds and after another 5 seconds, another 24 B: 24 followed by another 24 immediately C: 24 immediately and another 24 after 5 seconds D: After 5 seconds, 24 and 24 E: Undefined F: NaN G: None of these
	Bitcoin prices Axios Promises	JavaScript	Medium	2 mins	Solve
Review the following JavaScript code and pick the correct options: Assume that the API returns a successful 200 response code and a JSON object as the response body. What would the value of ‘a’ be after the code is executed?
	My Module Scope Javascript Es6 Closure	JavaScript	Medium	2 mins	Solve
What will the output of the following JavaScript code be?
	Promise Resolve Promises Async-Await Code Analysis Syntax Understanding	JavaScript	Medium	2 mins	Solve
What does the following code output?
	Throw, Try, Async Promises Async-Await Async/await	JavaScript	Easy	2 mins	Solve
What does the following JS code output?
	Registration Queue Logic Queues Sorting By Custom Order	Coding	Easy	30 mins	Solve
We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount. For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition. ⚠️⚠️⚠️ Note: - The first line of the input is the length of the array. The second line contains all the elements of the array. - The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function. - You need to "print" the final result (not return it) to pass the test cases. For the example discussed above, the input will be: 5 20 70 -40 30 -10 Your code needs to print the following to the standard output: 20 70 30 -40 -10
	Visitors Count Strings Logic String Parsing Character Counting	Coding	Medium	30 mins	Solve
A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. Example: Input: WWMMWWCCC Expected Output: 4W3C2M Explanation: ‘W’ has the highest count, then ‘C’, then ‘M’. ⚠️⚠️⚠️ Note: - The input is already parsed and passed to a function. - You need to "print" the final result (not return it) to pass the test cases. - If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’. - If any of them have the same count, the output should follow this order - M, W, C.

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Why you should use Pre-employment JavaScript Online Test?

The JavaScript Online Test makes use of scenario-based questions to test for on-the-job skills as opposed to theoretical knowledge, ensuring that candidates who do well on this screening test have the relavant skills. The questions are designed to covered following on-the-job aspects:

Understanding and applying JavaScript basics including arrays, objects, strings, and functions
Structuring and styling HTML DOM elements using JavaScript
Handling exceptions and errors in JavaScript
Working with user data and JSON in JavaScript
Applying ES6 features such as arrow functions, destructuring, and spreads
Utilizing higher-order functions and closures in JavaScript
Implementing object-oriented programming concepts including classes, constructors, and prototypal inheritance in JavaScript
Understanding and utilizing asynchronous JavaScript concepts such as the event loop, promises, and async/await

Once the test is sent to a candidate, the candidate receives a link in email to take the test. For each candidate, you will receive a detailed report with skills breakdown and benchmarks to shortlist the top candidates from your pool.

What topics are covered in the JavaScript Online Test?

JavaScript basics: JavaScript basics in this test cover arrays, objects, strings, and functions. It is important to measure this skill as a strong foundation in these concepts is crucial for writing efficient and effective JavaScript code.

Structuring and styling HTML DOM: This skill involves organizing and designing the structure of HTML elements using DOM (Document Object Model). It is measured to assess the candidate's ability to manipulate and style web page elements dynamically.

Errors and Exception Handling: Errors and exception handling refer to the ability to identify and handle errors in JavaScript code. This skill is essential to ensure smooth execution and maintenance of error-free applications, and thus, is evaluated in the test.

Working with user data and JSON: Assessing how well a candidate can interact with user data and JSON (JavaScript Object Notation) is important to gauge their ability to handle and process user input effectively and efficiently.

ES6: This skill covers advanced JavaScript concepts introduced in ECMAScript 6 (ES6), such as arrow functions, destructuring, and spreads. It is measured to evaluate a candidate's familiarity and proficiency with modern JavaScript syntax and features.

Higher-order functions and closures: Higher-order functions and closures are fundamental concepts in JavaScript that enable functional programming and code reusability. Measuring this skill helps assess a candidate's ability to write clean and maintainable code using these concepts.

OOP: This skill evaluates a candidate's understanding and implementation of Object-Oriented Programming (OOP) principles in JavaScript. It includes knowledge of classes, constructors, and prototypal inheritance, which play a crucial role in building scalable and modular applications.

Asynchronous JavaScript: Assessing a candidate's knowledge of handling asynchronous operations in JavaScript, including the event loop, promises, and async/await, is crucial to determine their ability to write responsive and efficient code that deals with time-consuming tasks.

Handling APIs: This skill measures the candidate's proficiency in consuming and integrating APIs (Application Programming Interfaces) in JavaScript. It includes knowledge of making API requests, handling responses, and parsing data, which are essential for building web applications that interact with external services and databases.

Full list of covered topics

The actual topics of the questions in the final test will depend on your job description and requirements. However, here's a list of topics you can expect the questions for JavaScript Online Test to be based on.

JavaScript syntax

Data types

Variables

Arrays

Objects

Strings

Functions

DOM manipulation

CSS styling

Error handling

Try...catch blocks

Throwing exceptions

User input

Validation

JSON parsing

JSON stringification

ES6 syntax

Arrow functions

Destructuring

Spread operator

Higher-order functions

Closures

Classes

Constructors

Prototypal inheritance

Event loop

Promises

Async/await

Fetch API

XHR requests

Response handling

Handling JSON data

Working with APIs

Access control

Cross-origin resource sharing

Authentication

Authorization

CORS

RESTful APIs

AJAX

Callback functions

Promisify

Error handling in asynchronous code

Timeouts and intervals

XML parsing

WebSockets

Local storage

Session storage

Browser cookies

Testing JavaScript code

Debugging

Performance optimization

Module systems

Bundler tools

Linting

Code quality

Accessibility

Responsive design

Mobile optimization

Single-page applications

Progressive Web Apps

Web workers

WebSockets

What roles can I use the JavaScript Online Test for?

JavaScript Developer
Front-end Developer
Full Stack Developer
Web Developer
UI/UX Developer
Web Application Developer
Mobile App Developer
Game Developer
Software Developer

How is the JavaScript Online Test customized for senior candidates?

For intermediate/ experienced candidates, we customize the assessment questions to include advanced topics and increase the difficulty level of the questions. This might include adding questions on topics like

Handling APIs in JavaScript
Applying JavaScript security best practices to prevent vulnerabilities
Working with different data structures in JavaScript such as sets and maps
Implementing data validation and sanitization techniques in JavaScript
Understanding and troubleshooting common JavaScript runtime errors
Working with JavaScript modules and module loaders
Implementing responsive web design using JavaScript
Performing browser compatibility testing for JavaScript

The coding question for experienced candidates will be of a higher difficulty level to evaluate more hands-on experience.

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Custom Questions

Ready-to-use Tests

Custom Tests

Custom Branding

Bulk Invites

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Have questions about the JavaScript Hiring Test?

What is JavaScript Online Test?

The JavaScript Online Test is designed to assess a candidate's understanding and proficiency in JavaScript. It is used by recruiters to evaluate technical skills for roles requiring JavaScript knowledge. This test is helpful in identifying candidates who have the right skills for JavaScript-related tasks.

Can I combine JavaScript Online Test with TypeScript questions?

Yes, recruiters can request a single custom test with multiple skills, including TypeScript. For more details on how we assess TypeScript skills, check out our TypeScript Online Test.

What topics are covered in the JavaScript Online Test?

The test covers JavaScript basics (arrays, objects, strings, functions), structuring and styling HTML DOM, errors and exception handling, working with user data and JSON, ES6 features (arrow functions, destructuring, spreads), higher-order functions and closures, OOP principles, asynchronous JavaScript, and handling APIs.

How to use JavaScript Online Test in my hiring process?

You can integrate the JavaScript Online Test as a pre-screening tool at the beginning of your recruitment process. Add a link to the test in your job post or directly invite candidates by email. This helps identify skilled candidates early in the hiring process.

Can I test JavaScript and NodeJS together in a test?

Yes, you can test both JavaScript and NodeJS together. This is recommended to assess full-stack capabilities. Check out our combo test for more details: JavaScript & NodeJS Test.

What are the main Front End developer tests?

Here are some important Front End developer tests:

Can I combine multiple skills into one custom assessment?

Yes, absolutely. Custom assessments are set up based on your job description, and will include questions on all must-have skills you specify. Here's a quick guide on how you can request a custom test.

Do you have any anti-cheating or proctoring features in place?

We have the following anti-cheating features in place:

Non-googleable questions
IP proctoring
Screen proctoring
Web proctoring
Webcam proctoring
Plagiarism detection
Secure browser
Copy paste protection

Read more about the proctoring features.

How do I interpret test scores?

The primary thing to keep in mind is that an assessment is an elimination tool, not a selection tool. A skills assessment is optimized to help you eliminate candidates who are not technically qualified for the role, it is not optimized to help you find the best candidate for the role. So the ideal way to use an assessment is to decide a threshold score (typically 55%, we help you benchmark) and invite all candidates who score above the threshold for the next rounds of interview.

What experience level can I use this test for?

Each Adaface assessment is customized to your job description/ ideal candidate persona (our subject matter experts will pick the right questions for your assessment from our library of 10000+ questions). This assessment can be customized for any experience level.

Does every candidate get the same questions?

Yes, it makes it much easier for you to compare candidates. Options for MCQ questions and the order of questions are randomized. We have anti-cheating/ proctoring features in place. In our enterprise plan, we also have the option to create multiple versions of the same assessment with questions of similar difficulty levels.

I'm a candidate. Can I try a practice test?

No. Unfortunately, we do not support practice tests at the moment. However, you can use our sample questions for practice.

What is the cost of using this test?

You can check out our pricing plans.

Can I get a free trial?

Yes, you can sign up for free and preview this test.

I just moved to a paid plan. How can I request a custom assessment?

Here is a quick guide on how to request a custom assessment on Adaface.

View sample scorecard

Along with scorecards that report the performance of the candidate in detail, you also receive a comparative analysis against the company average and industry standards.

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