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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:

  • JavaScript Syntax
  • Asynchronous JS
  • React Hooks
  • Redux State Management
  • Redux Actions and Selectors
  • JavaScript ES6
  • React Fundamentals
  • React Component Lifecycle
  • Redux API Handling
  • JavaScript Coding

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9 reasons why
9 reasons why

Adaface React & Redux Test is the most accurate way to shortlist Frontend 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.

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

  • Able to effectively use React.js to build dynamic user interfaces
  • Capable of understanding and implementing Redux for state management
  • Proficient in JavaScript syntax and ES6 features
  • Skilled in handling asynchronous JavaScript operations
  • Experienced with React component lifecycle methods
  • Adept at utilizing React hooks for functional components
  • Competent in handling API requests and responses with Redux
  • Proficient in writing Redux actions and selectors
  • Capable of coding in JavaScript and solving programming problems
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.

View sample questions

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
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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.

How we design questions

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
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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
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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
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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

Hard

Context re-renders
React Context API
Conditional Rendering
Component Lifecycle State
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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

Hooks with Conditional Rendering
Hooks
Conditional Rendering
Event Handling
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Consider a React functional component that utilizes various hooks and conditional rendering. The component is designed to fetch and display a list of items from an API, with the ability to filter the list based on user input. Here's the pseudo-code structure:
 image
In this component, which of the following is a potential issue or inefficiency?
A: The component will re-render excessively due to the `setFilter` call.
B: The `useEffect` hook will run on every render, causing performance issues.
C: The `fetchItems` function may cause a memory leak if the component unmounts during the fetch.
D: The `useMemo` hook for `filteredItems` is unnecessary and can be removed without impact.
E: The component will fail to display items when the filter is cleared.
F: There are no significant issues; the component is implemented optimally.

Medium

Rhyme Reducer
Reducer functions
Immutable update patterns
Lazy initialization
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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

Hard

State Handling with Custom Hooks
Custom Hooks
Context API
Event Handling
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Consider a React application where a custom hook `useComplexState` is defined to manage a complex state object. The application also uses the Context API to pass down the state and dispatch function. Below is the pseudo-code for the custom hook and a component using it:
 image
Given this setup, which of the following statements best describes the potential issue or challenge with `MyComponent`?
A: The component will not re-render when the global state changes.
B: The `fetchData` function will cause an infinite loop of re-renders.
C: The component will lose its state when the global state updates.
D: There will be a memory leak due to improper cleanup in `useEffect`.
E: The `dispatch` function from `useComplexState` will conflict with the global dispatch.
F: There is no issue; the component is implemented correctly.

Medium

Async Await Promises
Promises
Async-Await
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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

Medium

Bitcoin prices
Axios
Promises
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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
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What will the output of the following JavaScript code be?
 image
 image

Medium

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

Easy

Throw, Try, Async
Promises
Async-Await
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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
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Medium

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

2 mins

Redux
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Medium

Direct State Mutation in Redux
JavaScript ES6
Reducers
Actions
Mutations

3 mins

Redux
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Hard

Context re-renders
React Context API
Conditional Rendering
Component Lifecycle State

3 mins

React
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Medium

Hooks with Conditional Rendering
Hooks
Conditional Rendering
Event Handling

3 mins

React
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Medium

Rhyme Reducer
Reducer functions
Immutable update patterns
Lazy initialization

3 mins

React
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Hard

State Handling with Custom Hooks
Custom Hooks
Context API
Event Handling

3 mins

React
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Medium

Async Await Promises
Promises
Async-Await

2 mins

JavaScript
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Medium

Bitcoin prices
Axios
Promises

2 mins

JavaScript
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Medium

My Module
Scope

2 mins

JavaScript
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Medium

Promise Resolve
Promises
Async-Await

2 mins

JavaScript
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Easy

Throw, Try, Async
Promises
Async-Await

2 mins

JavaScript
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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
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Debugging Redux with Complex State and Action
JavaScript ES6
Reducers
Actions
Immutability
Object manipulation
Redux
Medium2 mins
Try practice test
Direct State Mutation in Redux
JavaScript ES6
Reducers
Actions
Mutations
Redux
Medium3 mins
Try practice test
Context re-renders
React Context API
Conditional Rendering
Component Lifecycle State
React
Hard3 mins
Try practice test
Hooks with Conditional Rendering
Hooks
Conditional Rendering
Event Handling
React
Medium3 mins
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Rhyme Reducer
Reducer functions
Immutable update patterns
Lazy initialization
React
Medium3 mins
Try practice test
State Handling with Custom Hooks
Custom Hooks
Context API
Event Handling
React
Hard3 mins
Try practice test
Async Await Promises
Promises
Async-Await
JavaScript
Medium2 mins
Try practice test
Bitcoin prices
Axios
Promises
JavaScript
Medium2 mins
Try practice test
My Module
Scope
JavaScript
Medium2 mins
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Promise Resolve
Promises
Async-Await
JavaScript
Medium2 mins
Try practice test
Throw, Try, Async
Promises
Async-Await
JavaScript
Easy2 mins
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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

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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.

Science behind Adaface tests
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

View sample scorecard
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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


Learn more

About the React & Redux Assessment Test

Why you should use Pre-employment React & Redux Online Test?

The React & Redux 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 the syntax and basic functions of JavaScript.
  • Applying JavaScript ES6 features such as arrow functions, template literals, and destructuring assignments.
  • Working with asynchronous JavaScript including promises and async/await.
  • Implementing React fundamentals like components, props, and state management.
  • Utilizing React hooks for functional component state management.
  • Understanding the React component lifecycle and using lifecycle methods.
  • Managing global state using Redux state management.
  • Handling asynchronous API requests using Redux.
  • Creating Redux actions and selectors for efficient state management.
  • Implementing JavaScript coding solutions for various problems.

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 React & Redux Online Test?

  • JavaScript Syntax

    JavaScript Syntax refers to the set of rules that dictate how JavaScript code should be written and structured. It includes concepts such as variables, functions, conditionals, loops, and operators. This skill is important to measure in the test as it forms the foundation of JavaScript programming and is crucial for any developer working with React and Redux.

  • JavaScript ES6

    JavaScript ES6, also known as ECMAScript 2015, introduced several new features and improvements to the JavaScript language. It includes arrow functions, const and let variables, template literals, and more. Assessing this skill in the test helps determine a candidate's familiarity with modern JavaScript syntax and their ability to write concise and efficient code.

  • Asynchronous JS

    Asynchronous JavaScript involves executing code without blocking the execution of other code. It typically involves callbacks, promises, and async/await syntax to handle tasks such as network requests or file operations. This skill is important to measure as React and Redux often require working with asynchronous operations, such as fetching data from APIs.

  • React Fundamentals

    React Fundamentals cover the core concepts and principles of the React library. This includes learning about components, props, state, lifecycle methods, JSX syntax, and handling events. Measuring this skill helps gauge a candidate's knowledge and understanding of React's building blocks and their ability to create reusable and efficient UI components.

  • React Hooks

    React Hooks are a set of functions introduced in React 16.8 that allow developers to use state and other React features without writing class components. With hooks, functional components can have their own state, lifecycle methods, and other functionalities. This skill is important to measure as hooks have become the preferred way of writing React components and understanding them is essential for modern React development.

  • React Component Lifecycle

    The React component lifecycle refers to the different phases that a React component goes through from its creation to its removal from the DOM. It includes methods such as componentDidMount, componentDidUpdate, and componentWillUnmount. Assessing this skill helps evaluate a candidate's understanding of component lifecycle methods and their ability to utilize them effectively for tasks like data fetching or cleanup operations.

  • Redux State Management

    Redux is a state management library for JavaScript applications, often used in conjunction with React. It provides a predictable state container and enables centralized management of application state. Measuring this skill in the test allows recruiters to assess a candidate's proficiency in using Redux to manage complex state and handle data flow within a React application.

  • Redux API Handling

    Redux API Handling involves writing actions, reducers, and middleware to handle asynchronous operations, such as making API requests in a Redux application. It includes concepts like thunk middleware, handling loading and error states, and updating the Redux store with fetched data. Evaluating this skill helps determine a candidate's ability to integrate Redux with APIs and manage async workflows effectively.

  • Redux Actions and Selectors

    Redux Actions are plain JavaScript objects that represent unique events that can happen in an application. Selectors are functions used to extract and derive specific data from the Redux store. Assessing this skill helps gauge a candidate's understanding and implementation of Redux actions for state updates and selectors for efficient data retrieval in a Redux-based application.

  • JavaScript Coding

    JavaScript Coding refers to the ability to write clean, efficient, and maintainable code using JavaScript. It encompasses concepts like algorithmic problem-solving, data manipulation, and applying best practices. Measuring this skill in the test helps determine a candidate's overall JavaScript proficiency and their ability to write quality code when working with React and Redux.

  • 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 React & Redux Online Test to be based on.

    JavaScript Syntax
    JavaScript ES6
    Asynchronous JS
    React Fundamentals
    React Hooks
    React Component Lifecycle
    Redux State Management
    Redux API Handling
    Redux Actions and Selectors
    JavaScript Coding
    Functions
    Variables
    Data Types
    Operators
    Control Flow
    Arrays
    Objects
    Classes
    Promises
    Async/Await
    Closures
    Event Loop
    JSX
    Components
    Props
    State
    Lifecycle Methods
    Hooks
    Context API
    Higher-Order Components
    State Management
    Reducers
    Action Creators
    Redux Store
    Middleware
    Thunk
    Axios
    API Integration
    Selectors
    Immutable Data
    Testing with Jest
    Debugging
    Error Handling
    DOM Manipulation
    Event Handling
    AJAX
    Fetch API
    Destructuring
    Spread Syntax
    Arrow Functions
    Template Literals
    Rest Parameters
    Default Parameters
    Modules
    Import/Export
    Classes
    Inheritance
    Prototypes
    Arrays
    Array Methods
    Array Iteration
    Map
    Set
    Promises
    Generators
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What roles can I use the React & Redux Online Test for?

  • Frontend Developer
  • React Developer
  • Redux Developer
  • Senior Redux Developer

How is the React & Redux 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

  • Building scalable and maintainable React applications.
  • Optimizing performance in React applications.
  • Implementing code splitting and lazy loading in React applications.
  • Using React Router for client-side routing in React applications.
  • Integrating third-party libraries and frameworks with React applications.
  • Testing React components using libraries like Jest and Enzyme.
  • Implementing server-side rendering (SSR) in React applications.
  • Securing React applications by implementing authentication and authorization.
  • Implementing data caching and persistence in React applications.
  • Analyzing and fixing performance issues in React and Redux applications.
  • Designing and implementing scalable Redux architecture for large applications.

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

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 & Redux Hiring Test 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. 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.

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