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About the test:

The React & Redux Test uses scenario-based MCQs to evaluate candidates on their proficiency in JavaScript programming language and ReactJS development using Redux. The test has one coding question to evaluate hands-on JavaScript coding experience.

Covered skills:

  • Class-based components
  • Props
  • Functional components
  • State
See all covered skills

9 reasons why
9 reasons why

Adaface React & Redux Online Test is the most accurate way to shortlist React Developers



Reason #1

Tests for on-the-job skills

The React & Redux 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.

Non-googleable questions & proctoring features enable you to be comfortable with conducting assessments online. The React & Redux Online Test is ideal for helping recruiters identify which candidates have the skills to do well on the job.

Reason #2

No trick questions

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 & Redux Online Test will be non-googleable.

🧐 Question

Medium

Debugging Redux Actions and Reducers
JavaScript ES6
Reducers
Actions
Solve
A developer is working with a Redux application for managing todo items. After some changes to the code, they started facing a problem: When they try to add a new todo item, it doesn't appear on the list. However, deleting a todo item works as expected.

Here is the error message they see in the console when trying to add a todo: `Cannot read property 'undefined' of undefined.`

And here is the relevant Redux code:
 image
Which of the following changes will resolve the issue?
A: Change payload to todo in addTodo action creator.
B: Change action.todo to action.payload in todoReducer for ADD_TODO case.
C: Change action.todo to action.payload in todoReducer for ADD_TODO case and change action.index to action.payload for DELETE_TODO case.
D: Change payload to todo in addTodo action creator and index to payload in deleteTodo action creator.

Medium

Debugging Redux with Complex State and Action
JavaScript ES6
Reducers
Actions
Immutability
Object manipulation
Solve
A developer is working on a Redux application where each action carries an array of items, and each item is an object with an `id` and `value`. The state is an object where each key is an item's `id` and each value is the item's `value`. However, they notice that the `ADD_ITEMS` action isn't updating the state as expected.

Here is the relevant Redux code:
 image
What change should the developer make to correct the issue?
 image

Medium

Direct State Mutation in Redux
JavaScript ES6
Reducers
Actions
Mutations
Solve
A developer is creating a Redux application to manage a list of blog posts. Each post is represented by an object with id, title, and content properties.

The Redux state should store the post list as an array. The developer observes that the modifications to the posts are not reflecting in the components.

Here is an example of what the state could look like:
 image
Here is the relevant Redux code:
 image
Which of the following changes will resolve the issue?
 image

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

Medium

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
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

Debugging Redux Actions and Reducers
JavaScript ES6
Reducers
Actions
2 mins
Redux
Solve

Medium

Debugging Redux with Complex State and Action
JavaScript ES6
Reducers
Actions
Immutability
Object manipulation
2 mins
Redux
Solve

Medium

Direct State Mutation in Redux
JavaScript ES6
Reducers
Actions
Mutations
3 mins
Redux
Solve

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

Medium

Promise Resolve
Promises
Async-Await
2 mins
JavaScript
Solve

Easy

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

Easy

Registration Queue
Logic
Queues
30 mins
Coding
Solve

Medium

Visitors Count
Strings
Logic
30 mins
Coding
Solve
🧐 Question🔧 Skill💪 Difficulty⌛ Time
Debugging Redux Actions and Reducers
JavaScript ES6
Reducers
Actions
Redux
Medium2 mins
Solve
Debugging Redux with Complex State and Action
JavaScript ES6
Reducers
Actions
Immutability
Object manipulation
Redux
Medium2 mins
Solve
Direct State Mutation in Redux
JavaScript ES6
Reducers
Actions
Mutations
Redux
Medium3 mins
Solve
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
Medium2 mins
Solve
Throw, Try, Async
Promises
Async-Await
JavaScript
Easy2 mins
Solve
Registration Queue
Logic
Queues
Coding
Easy30 minsSolve
Visitors Count
Strings
Logic
Coding
Medium30 minsSolve
Reason #4

1200+ customers in 75 countries

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 & Redux 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 & Redux 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.

invite candidates
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.

test completion rate
Reason #9

Advanced Proctoring


What topics are covered in the React & Redux 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
Types and operators
Loops
Variables
Functions
Arrays
Objects
Strings
DOM
HTML/ CSS fundamentals
Closures
IIFE
OOPs
ES6
Math
Cookies
JSON
Async/Await
Promises
Arrows
Timers
Destructuring
Local storage
Session storage
Console
this', 'call', 'bind' keywords
Event handling
Exception handling
Form handling
Service workers
Computer fundamentals
Letter Coding
Number Coding
Substitution
Coding-Decoding Puzzles
Non-verbal Reasoning
SQL concepts
Business analysis
Coding-Decoding
Programming languages
Computer architecture
Basic DBMS concepts
SOLID principles
Automation systems
Decision making
Non-verbal Reasoning
Problem-solving approach
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

FAQs

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.

customers across world
Join 1200+ companies in 75+ countries.
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