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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
  • Communicating with Props
  • React State
See all covered skills

9 reasons why
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:
 image
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:
 image
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
 image
 image

Medium

Async Await Promises
Promises
Async-Await
Solve
What will the following code output?
 image
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

Easy

Bitcoin prices
Axios
Promises
Solve
Review the following JavaScript code and pick the correct options: 
 image
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?
 image
 image

Easy

Promise Resolve
Promises
Async-Await
Solve
What does the following code output? 
 image

Easy

Throw, Try, Async
Promises
Async-Await
Solve
What does the following JS code output?
 image

Easy

Registration Queue
Logic
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

Longest Road
logic
hashmaps
Solve
A startup company E-Motors is building driverless automated cars. The car contains a sensor that checks the road quality for the next N meters to decide the optimal speed at which the cars should move. We are given recorded data by the sensor in the form of an array, where each element of the array is the rating given to 1 meter of the road in sequence. 

The rating given by the sensor is from 1 to 100, where 100 represents the road with the best condition, and any rating above 60 is optimal. Find the longest stretch of road in meters that is categorized as optimal by the sensor.

The input is an array of "strings" which needs to be converted from string to integer/number inside the function.

Medium

Visitors Count
Strings
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

Medium

Error Boundaries and Event handlers
Error Boundaries
3 mins
React
Solve

Medium

Rhyme Reducer
Hooks
3 mins
React
Solve

Medium

Async Await Promises
Promises
Async-Await
2 mins
JavaScript
Solve

Easy

Bitcoin prices
Axios
Promises
2 mins
JavaScript
Solve

Medium

My Module
Scope
2 mins
JavaScript
Solve

Easy

Promise Resolve
Promises
Async-Await
2 mins
JavaScript
Solve

Easy

Throw, Try, Async
Promises
Async-Await
2 mins
JavaScript
Solve

Easy

Registration Queue
Logic
30 mins
Coding
Solve

Medium

Longest Road
logic
hashmaps
25 mins
Coding
Solve

Medium

Visitors Count
Strings
30 mins
Coding
Solve
🧐 Question🔧 Skill💪 Difficulty⌛ Time
Context re-renders
Context
React
Medium3 mins
Solve
Error Boundaries and Event handlers
Error Boundaries
React
Medium3 mins
Solve
Rhyme Reducer
Hooks
React
Medium3 mins
Solve
Async Await Promises
Promises
Async-Await
JavaScript
Medium2 mins
Solve
Bitcoin prices
Axios
Promises
JavaScript
Easy2 mins
Solve
My Module
Scope
JavaScript
Medium2 mins
Solve
Promise Resolve
Promises
Async-Await
JavaScript
Easy2 mins
Solve
Throw, Try, Async
Promises
Async-Await
JavaScript
Easy2 mins
Solve
Registration Queue
Logic
Coding
Easy30 minsSolve
Longest Road
logic
hashmaps
Coding
Medium25 minsSolve
Visitors Count
Strings
Coding
Medium30 minsSolve
Reason #4

1200+ customers in 75 countries

Brandon

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 & comparative results

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


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
Singapore government logo

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

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.

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.

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Try the most candidate friendly skills assessment tool today.
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