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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
  • 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

9 reasons why
9 reasons why

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



Reason #1

Tests for on-the-job skills

The ReactJS 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:

  • Building content with JSX
  • Communicating with Props
  • Implementing Class-Based Components
  • Managing React State
  • Working with React Lifecycle Methods
  • Handling User Input with Forms and Events
  • Making API Requests with React
  • Building Lists of Records
  • Accessing DOM with Refs
  • Understanding Hooks in React
  • Component and Route Navigation
  • Deploying a React App
  • Integrating React with State Management Libraries
  • Handling Authentication with React
  • Using the Context System with React
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
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.js Online Test will be non-googleable.

🧐 Question

Hard

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

Hooks with Conditional Rendering
Hooks
Conditional Rendering
Event Handling
Solve
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
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

Hard

State Handling with Custom Hooks
Custom Hooks
Context API
Event Handling
Solve
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
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

Medium

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

Hard

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

3 mins

React
Solve

Medium

Hooks with Conditional Rendering
Hooks
Conditional Rendering
Event Handling

3 mins

React
Solve

Medium

Rhyme Reducer
Reducer functions
Immutable update patterns
Lazy initialization

3 mins

React
Solve

Hard

State Handling with Custom Hooks
Custom Hooks
Context API
Event Handling

3 mins

React
Solve

Medium

Async Await Promises
Promises
Async-Await

2 mins

JavaScript
Solve

Medium

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
Context re-renders
React Context API
Conditional Rendering
Component Lifecycle State
React
Hard3 mins
Solve
Hooks with Conditional Rendering
Hooks
Conditional Rendering
Event Handling
React
Medium3 mins
Solve
Rhyme Reducer
Reducer functions
Immutable update patterns
Lazy initialization
React
Medium3 mins
Solve
State Handling with Custom Hooks
Custom Hooks
Context API
Event Handling
React
Hard3 mins
Solve
Async Await Promises
Promises
Async-Await
JavaScript
Medium2 mins
Solve
Bitcoin prices
Axios
Promises
JavaScript
Medium2 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.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.

Science behind Adaface tests
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.

invite candidates
Reason #7

Detailed scorecards & benchmarks

View sample scorecard
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 ReactJS Assessment Test

Why you should use Pre-employment ReactJS Online Test?

The React.js 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:

  • Building content with JSX
  • Communicating with Props
  • Class-Based Components
  • React State
  • Lifecycle Methods
  • Handling User Input with Forms and Events
  • Making API Requests with React
  • Building Lists of Records
  • Using Refs for DOM Access
  • Understanding Hooks in React

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 ReactJS Online Test?

  • Building Content with JSX

    Building Content with JSX means creating user interface components in React using JSX syntax. JSX is a syntax extension for JavaScript that allows you to write HTML-like code in your JavaScript files. This skill should be measured in the test to assess a candidate's ability to understand and use JSX to create dynamic and reusable UI components.

  • Communicating with Props

    Communicating with Props involves passing data from one component to another in React. Props are a way to pass information from a parent component to its child component. This skill should be measured in the test to evaluate a candidate's ability to design and implement a component hierarchy that effectively communicates data between components.

  • Class-Based Components

    Class-Based Components are a way to define and create reusable components in React. They are implemented as JavaScript classes that extend the base React Component class. This skill should be measured in the test to assess a candidate's understanding of class-based component syntax and their ability to create and manage component state using class methods.

  • React State

    React State refers to the state management system provided by React. State allows components to hold and manage their own data, which can be updated and rendered automatically in response to changes. This skill should be measured in the test to evaluate a candidate's understanding of state management in React and their ability to create dynamic and interactive UI components that respond to user actions and data changes.

  • Lifecycle Methods

    Lifecycle Methods in React are special methods that are automatically called at specific points during a component's lifecycle, such as when it is mounted or updated. They provide hooks for performing tasks like fetching data, subscribing to events, or updating the component's state. This skill should be measured in the test to assess a candidate's familiarity with the lifecycle methods in React and their ability to utilize them effectively to control and manage component behavior.

  • Handling User Input with Forms and Events

    Handling User Input with Forms and Events involves capturing and processing user input in React. This skill should be measured in the test to evaluate a candidate's ability to create controlled form components, handle form submissions, and respond to user events such as clicks, key presses, and mouse movements.

  • Making API Requests with React

    Making API Requests with React involves fetching data from external APIs and integrating it into React components. This skill should be measured in the test to assess a candidate's knowledge of using tools like the Fetch API or Axios to make asynchronous requests, handle responses, and update component state with the retrieved data.

  • Building Lists of Records

    Building Lists of Records in React refers to rendering dynamic lists of items based on data. This skill should be measured in the test to evaluate a candidate's ability to map over an array of data, generate dynamic list components, and render them efficiently in React.

  • Using Refs for DOM Access

    Using Refs for DOM Access allows direct access to the underlying DOM elements in React components. Refs provide a way to interact with the DOM imperatively, such as obtaining the value of an input field or triggering a focus event. This skill should be measured in the test to assess a candidate's understanding of refs and their ability to use them effectively for DOM manipulation and access.

  • Understanding Hooks in React

    Understanding Hooks in React is about utilizing the Hooks feature introduced in React to write functional components with state and lifecycle features. Hooks provide a way to use React features like state and lifecycle methods in functional components, making them more easy to write, understand, and test. This skill should be measured in the test to evaluate a candidate's familiarity with Hooks and their ability to leverage them to build functional, stateful components in React.

  • Component and Route Navigation

    Component and Route Navigation in React involves managing the navigation and routing within a React application. This skill should be measured in the test to assess a candidate's understanding of React Router or other routing libraries, and their ability to navigate between different components or routes based on user interactions or programmatic logic.

  • Deploying a React App

    Deploying a React App means making a React application available to users by deploying it to a hosting platform or server. This skill should be measured in the test to evaluate a candidate's knowledge of the deployment process for React applications, including build optimization, environment configuration, and deployment strategies.

  • Integrating React with State management libraries

    Integrating React with state management libraries involves using libraries like Redux or MobX to manage the global state of a React application. This skill should be measured in the test to assess a candidate's familiarity with state management concepts and their ability to integrate and utilize state management libraries in React applications to manage complex data flows and shared state.

  • Handling Authentication with React

    Handling Authentication with React involves implementing user authentication and authorization in a React application. This skill should be measured in the test to evaluate a candidate's ability to implement authentication flows, handle user sessions, protect routes, and securely manage user credentials and authentication tokens within a React application.

  • Using the Context System with React

    Using the Context System with React allows sharing data or state between components without passing props through every level of the component tree. Context provides a way to access a value or state from any component within the context tree. This skill should be measured in the test to assess a candidate's understanding of the Context API in React and their ability to utilize it to share data and manage application-wide state in a more efficient and scalable way.

  • 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.js Online Test to be based on.

    JSX Syntax
    JSX Expressions
    Component Rendering
    Component Props
    Component Composition
    Component State
    State and Props updates
    Lifecycle Methods: componentDidMount
    Lifecycle Methods: componentDidUpdate
    Lifecycle Methods: componentWillUnmount
    Event Handling
    Form Handling
    API Requests with Fetch
    API Requests with Axios
    Data Manipulation
    Rendering Lists
    DOM Access with Refs
    Understanding useState
    Understanding useEffect
    React Router
    React Router: Route Parameters
    React Router: Redirects
    Deployment Options
    Integrating with Redux
    Integrating with MobX
    User Authentication
    Context System: Provider and Consumer
    Context System: useContext
    Context System: useReducer
    Context System: Custom Hooks
    Context System: Multiple Contexts

What roles can I use the ReactJS 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

How is the ReactJS 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

  • Component and Route Navigation
  • Deploying a React App
  • Integrating React with State management libraries
  • Handling Authentication with React
  • Using the Context System with React
  • Testing React Components
  • Performance Optimization in React
  • Server-Side Rendering with React
  • Frontend Security in React
  • Building Progressive Web Apps with React

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

ReactJS Hiring 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. 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.

Ready to use the Adaface React.js Online Test?
Ready to use the Adaface React.js Online Test?
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