Why You Should Use This React Test

This test evaluates the candidates on the following skills: React fundamentals around State, props and the component lifecycle Understanding of Virtual DOM and how React performs reconciliation Leveraging lifecycle methods to make AJAX calls React Navigation and data transfer between different screens Handling asynchronous code using callbacks, promises, generators and async functions Connecting React applications with state management libraries Understanding new class syntax and creating instance methods Creating Hooks and Context structures Along with React, the test evaluates candidates on JavaScript coding ability using scenario-based MCQs and coding questions. The insights generated from this React assessment can be used by recruiters and hiring managers to identify the best candidates for React roles.

ReactJS Online Test

About the test:

The React test uses scenario-based MCQ questions to evaluate the understanding of React component lifecycle, the ability to work with JSX, user events, React State, functional components, and Hooks to create dynamic React applications. The test has JavaScript MCQs to assess ES6 fundamentals, DOM, Fetch, Promises and Async / Await. The test includes coding questions to evaluate hands-on JavaScript programming skills.

Covered skills:

Building Content with JSX
Class-Based Components
Lifecycle Methods
Making API Requests with React
Using Refs for DOM Access
Component and Route Navigation
Integrating React with State management libraries
Using the Context System with React

Communicating with Props
React State
Handling User Input with Forms and Events
Building Lists of Records
Understanding Hooks in React
Deploying a React App
Handling Authentication with React

See all covered skills

Preview this test

View sample scorecard

9 reasons why

Adaface ReactJS Online Test is the most accurate way to shortlist ReactJS Developers

Reason #1

Tests for on-the-job skills

This test evaluates the candidates on the following skills:

React fundamentals around State, props and the component lifecycle
Understanding of Virtual DOM and how React performs reconciliation
Leveraging lifecycle methods to make AJAX calls
React Navigation and data transfer between different screens
Handling asynchronous code using callbacks, promises, generators and async functions
Connecting React applications with state management libraries
Understanding new class syntax and creating instance methods
Creating Hooks and Context structures

Along with React, the test evaluates candidates on JavaScript coding ability using scenario-based MCQs and coding questions.

The insights generated from this React assessment can be used by recruiters and hiring managers to identify the best candidates for React roles.

Reason #2

No trick questions

Traditional assessment tools use trick questions and puzzles for the screening, which creates a lot of frustration among candidates about having to go through irrelevant screening assessments.

The main reason we started Adaface is that traditional pre-employment assessment platforms are not a fair way for companies to evaluate candidates. At Adaface, our mission is to help companies find great candidates by assessing on-the-job skills required for a role.

Why we started Adaface ->

Reason #3

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.

These are just a small sample from our library of 10,000+ questions. The actual questions on this React.js Online Test will be non-googleable.

🧐 Question
Medium Context re-renders Context	Solve
Review the following React code: Pick the correct statements: A: The code renders 10 INDIAN RUPEE B: The code renders 10 SINGAPORE DOLLAR C: The code does not render anything and throws an error since JavaScript objects are not valid as React children D: When the currency portion is clicked, the parent component is re-rendered E: When the currency portion is clicked, parent component will skip the re-render because shouldComponentUpdate returns false F: Parent component can be converted to a functional component with memoization (useMemo or memo) to avoid the re-render
Medium Error Boundaries and Event handlers Error Boundaries	Solve
Review the following React code: Notice that clicking on ‘Click Me’ will invoke handleClick which will throw an error. Also note that, ErrorBoundaryOne throws the error in getDerivedStateFromError. What will be rendered once ‘Click Me’ is clicked? A: ErrorBoundaryOne will catch the error of MyComponent and <h1>C</h1> will be rendered B: ErrorBoundaryOne will catch the error of MyComponent and its own error, <h1>C</h1> will be rendered C: ErrorBoundaryTwo will catch the error of MyComponent and ErrorBoundaryOne, <h1>B</h1> will be rendered D: ErrorBoundaryTwo will catch the error of MyComponent and ErrorBoundaryOne, <h1>B</h1><h1>C</h1> will be rendered E: ErrorBoundaryTwo will catch the error of ErrorBoundaryOne. ErrorBoundaryOne will catch the error of MyComponent, <h1>B</h1> will be rendered F: Error thrown in the click handler is not caught by any error boundary, ‘Click Me’ button will be rendered
Medium Rhyme Reducer Hooks	Solve
Which of the following React code snippets - triggers the reducer ‘rhymeReducer’ to update the ‘song’ value to ‘Jack and Jill’ - renders the updated ‘song’ value - does not produce any errors/warnings
Medium Async Await Promises Promises Async-Await	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	Solve
What will the output of the following JavaScript code be?
Medium Promise Resolve Promises Async-Await	Solve
What does the following code output?
Easy Throw, Try, Async Promises Async-Await	Solve
What does the following JS code output?
Easy Registration Queue Logic Queues	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	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 Context re-renders Context	3 mins React	Solve
Review the following React code: Pick the correct statements: A: The code renders 10 INDIAN RUPEE B: The code renders 10 SINGAPORE DOLLAR C: The code does not render anything and throws an error since JavaScript objects are not valid as React children D: When the currency portion is clicked, the parent component is re-rendered E: When the currency portion is clicked, parent component will skip the re-render because shouldComponentUpdate returns false F: Parent component can be converted to a functional component with memoization (useMemo or memo) to avoid the re-render
	Medium Error Boundaries and Event handlers Error Boundaries	3 mins React	Solve
Review the following React code: Notice that clicking on ‘Click Me’ will invoke handleClick which will throw an error. Also note that, ErrorBoundaryOne throws the error in getDerivedStateFromError. What will be rendered once ‘Click Me’ is clicked? A: ErrorBoundaryOne will catch the error of MyComponent and <h1>C</h1> will be rendered B: ErrorBoundaryOne will catch the error of MyComponent and its own error, <h1>C</h1> will be rendered C: ErrorBoundaryTwo will catch the error of MyComponent and ErrorBoundaryOne, <h1>B</h1> will be rendered D: ErrorBoundaryTwo will catch the error of MyComponent and ErrorBoundaryOne, <h1>B</h1><h1>C</h1> will be rendered E: ErrorBoundaryTwo will catch the error of ErrorBoundaryOne. ErrorBoundaryOne will catch the error of MyComponent, <h1>B</h1> will be rendered F: Error thrown in the click handler is not caught by any error boundary, ‘Click Me’ button will be rendered
	Medium Rhyme Reducer Hooks	3 mins React	Solve
Which of the following React code snippets - triggers the reducer ‘rhymeReducer’ to update the ‘song’ value to ‘Jack and Jill’ - renders the updated ‘song’ value - does not produce any errors/warnings
	Medium Async Await Promises Promises Async-Await	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	2 mins JavaScript	Solve
What will the output of the following JavaScript code be?
	Medium Promise Resolve Promises Async-Await	2 mins JavaScript	Solve
What does the following code output?
	Easy Throw, Try, Async Promises Async-Await	2 mins JavaScript	Solve
What does the following JS code output?
	Easy Registration Queue Logic Queues	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	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
	Context re-renders Context	React	Medium	3 mins	Solve
Review the following React code: Pick the correct statements: A: The code renders 10 INDIAN RUPEE B: The code renders 10 SINGAPORE DOLLAR C: The code does not render anything and throws an error since JavaScript objects are not valid as React children D: When the currency portion is clicked, the parent component is re-rendered E: When the currency portion is clicked, parent component will skip the re-render because shouldComponentUpdate returns false F: Parent component can be converted to a functional component with memoization (useMemo or memo) to avoid the re-render
	Error Boundaries and Event handlers Error Boundaries	React	Medium	3 mins	Solve
Review the following React code: Notice that clicking on ‘Click Me’ will invoke handleClick which will throw an error. Also note that, ErrorBoundaryOne throws the error in getDerivedStateFromError. What will be rendered once ‘Click Me’ is clicked? A: ErrorBoundaryOne will catch the error of MyComponent and <h1>C</h1> will be rendered B: ErrorBoundaryOne will catch the error of MyComponent and its own error, <h1>C</h1> will be rendered C: ErrorBoundaryTwo will catch the error of MyComponent and ErrorBoundaryOne, <h1>B</h1> will be rendered D: ErrorBoundaryTwo will catch the error of MyComponent and ErrorBoundaryOne, <h1>B</h1><h1>C</h1> will be rendered E: ErrorBoundaryTwo will catch the error of ErrorBoundaryOne. ErrorBoundaryOne will catch the error of MyComponent, <h1>B</h1> will be rendered F: Error thrown in the click handler is not caught by any error boundary, ‘Click Me’ button will be rendered
	Rhyme Reducer Hooks	React	Medium	3 mins	Solve
Which of the following React code snippets - triggers the reducer ‘rhymeReducer’ to update the ‘song’ value to ‘Jack and Jill’ - renders the updated ‘song’ value - does not produce any errors/warnings
	Async Await Promises Promises Async-Await	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	Medium	2 mins	Solve
What will the output of the following JavaScript code be?
	Promise Resolve Promises Async-Await	JavaScript	Medium	2 mins	Solve
What does the following code output?
	Throw, Try, Async Promises Async-Await	JavaScript	Easy	2 mins	Solve
What does the following JS code output?
	Registration Queue Logic Queues	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	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.

Reason #4

1200+ customers in 75 countries

With Adaface, we were able to optimise our initial screening process by upwards of 75%, freeing up precious time for both hiring managers and our talent acquisition team alike!

Brandon Lee, Head of People, Love, Bonito

Reason #5

Designed for elimination, not selection

The most important thing while implementing the pre-employment React.js Online Test in your hiring process is that it is an elimination tool, not a selection tool. In other words: you want to use the test to eliminate the candidates who do poorly on the test, not to select the candidates who come out at the top. While they are super valuable, pre-employment tests do not paint the entire picture of a candidate’s abilities, knowledge, and motivations. Multiple easy questions are more predictive of a candidate's ability than fewer hard questions. Harder questions are often "trick" based questions, which do not provide any meaningful signal about the candidate's skillset.

Reason #6

1 click candidate invites

Email invites: You can send candidates an email invite to the React.js Online Test from your dashboard by entering their email address.

Public link: You can create a public link for each test that you can share with candidates.

API or integrations: You can invite candidates directly from your ATS by using our pre-built integrations with popular ATS systems or building a custom integration with your in-house ATS.

Reason #7

Detailed scorecards & benchmarks

Reason #8

High completion rate

Adaface tests are conversational, low-stress, and take just 25-40 mins to complete.

This is why Adaface has the highest test-completion rate (86%), which is more than 2x better than traditional assessments.

Reason #9

Advanced Proctoring

Preview this test

View sample scorecard

How do you customize the test for Senior React developers?

The questions used for Senior React developer tests are based on advanced React topics. Here are a few advanced topics we cover:

Using Babel and Webpack to transpile and bundle code
Understanding how JavaScript handles asynchronous code using the Event Loop with the Stack, Heap and Queue
Using React Portals to render Children Outside the DOM Hierarchy
Cleaning up code using arrow functions and master method binding without using the bind keyword
Handling Authentication with React
Improving the performance of React applications (Code Splitting, Load Balancing, Caching, Code Optimizations)
Working with Older Versions of React
Replacing State management libraries like Redux with Context
Implementing animations in React

What roles can I use the React.js Online Test for?

ReactJS Developer
Software Developer (React)
Full Stack Web Developer
Front End Engineer (React)
Software Engineer (ReactJS)
Web Developer
Senior ReactJS Developer
JavaScript Engineer (React)
Senior Web Engineer

What topics are covered in the ReactJS Online Test?

Class-based components

Functional components

Props

State

Events

Lists

Built-in Hooks

Custom Hooks

Styled Components

CSS Modules

Fragments

Portals

Dealing with side effects

Transitional states

Forms and Inputs

State Management

Routing & Navigation

Authentication

Animations

Webpack

Flexbox

Context

useState

useEffect

useReducer

useContext

Reducer

JWT Authentication

Preview this test

View sample scorecard

The hiring managers felt that through the technical questions that they asked during the panel interviews, they were able to tell which candidates had better scores, and differentiated with those who did not score as well. They are highly satisfied with the quality of candidates shortlisted with the Adaface screening.

85%

reduction in screening time

View Full Case Study

React.js Online Test FAQs

Can I evaluate React and TypeScript in the same test?

Yes. Once you move to a paid plan, you can request for a custom assessment. We customize the assessment according to your job description and support evaluating multiple skills in the same assessment.

Can I evaluate React, JavaScript and HTML/ CSS in the same test?

Yes. The test already comes with MCQs to evaluate JavaScript fundamentals and coding questions to evaluate hands-on JavaScript programming skills. We can customize the test to include MCQ questions to evaluate HTML/ CSS skills.

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.

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
Web proctoring
Webcam proctoring
Plagiarism detection
Secure browser

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.