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JavaScript, HTML/CSS & React Online Test

About the test:

The JavaScript, HTML/CSS & React Test uses scenario-based MCQs to evaluate candidates on their proficiency in JavaScript programming language, HTML/CSS markup, and React library. The test assesses candidates' understanding of topics such as DOM manipulation, event handling, component lifecycle, state management, props and rendering, and CSS styling. Candidates are evaluated on their ability to use these technologies to solve real-world problems and develop responsive and interactive web applications.

Covered skills:

  • JavaScript Basics
  • JS OOPs
  • Asynchronous Node.js and promises
  • React Component Lifecycle
  • CSS Box model
  • Responsive CSS
  • JS ES6
  • Handling APIs
  • Building components with JSX
  • React Hooks and functional components
  • Flexbox and Grid layouts
  • JavaScript Programming

9 reasons why
9 reasons why

Adaface JavaScript, HTML/CSS & React Test is the most accurate way to shortlist Full Stack Developers



Reason #1

Tests for on-the-job skills

The JavaScript, HTML/CSS & React 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:

  • Ability to efficiently handle exceptions and errors
  • Proficiency in ES6 syntax and concepts
  • Understanding of Object-Oriented Programming principles in JavaScript
  • Knowledge of working with APIs and handling asynchronous operations
  • Experience in building components with JSX
  • Familiarity with the React Component Lifecycle
  • Proficiency in using React Hooks and functional components
  • Understanding of CSS Box model and its application
  • Proficiency in creating responsive CSS designs
  • Strong JavaScript programming skills
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 JavaScript, HTML/CSS & React Test will be non-googleable.

🧐 Question

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

Background Properties
Solve
Consider the following shorthand CSS example:

background: #f7f7f7 url(jolie.jpg) no-repeat scroll 0px 0px;

Which of the following show the individual background properties represented by the shorthand:
 image

Easy

Colorful sentences
Solve
Our intern is writing a colorful blog post, and has written the following code. What colors will the sentences be?
 image
A: Sentence 1 will be gray, Sentence 2 will be pink.
B: Both sentences will be gray.
C: Sentence 1 will be pink, Sentence 2 will be gray.
D: Both sentences will be pink.
E: The code does not make sense; will throw an error.

Easy

Links
Solve
In the following HTML, what will be the color of link with class "mark"
 image

Medium

Let's Hack
CSS Property
Solve
Consider the following HTML and CSS:
 image
 image
Which additional CSS rule(s) will render the following image? Choose ALL that apply.
 image
A:
div{
  flex-direction : column;
  align-items : center;
}
B:
div{
  flex-direction : row;
  align-items: center;
}
C:
div{
  flex-direction: column;
  justify-content: center;
}
D:
div{
  flex-direction: row;
  justify-content: center;
}

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.

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

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

Background Properties

2 mins

HTML/CSS
Solve

Easy

Colorful sentences

2 mins

HTML/CSS
Solve

Easy

Links

2 mins

HTML/CSS
Solve

Medium

Let's Hack
CSS Property

3 mins

HTML/CSS
Solve

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

Easy

Registration Queue
Logic
Queues

30 mins

Coding
Solve

Medium

Visitors Count
Strings
Logic

30 mins

Coding
Solve
🧐 Question🔧 Skill💪 Difficulty⌛ Time
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
Background Properties
HTML/CSS
Easy2 mins
Solve
Colorful sentences
HTML/CSS
Easy2 mins
Solve
Links
HTML/CSS
Easy2 mins
Solve
Let's Hack
CSS Property
HTML/CSS
Medium3 mins
Solve
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
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 JavaScript, HTML/CSS & React 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 JavaScript, HTML/CSS & React 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 JavaScript, HTML/CSS & React Assessment Test

Why you should use Pre-employment JavaScript, HTML/CSS & React Online Test?

The JavaScript, HTML/CSS & React 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 JavaScript syntax and fundamentals
  • Knowledge of ES6 features and usage
  • Ability to write object-oriented JavaScript code
  • Experience in handling APIs and making HTTP calls
  • Proficiency in working with asynchronous Node.js and promises
  • Building reusable components with JSX in React
  • Understanding the React Component Lifecycle
  • Expertise in using React Hooks and functional components
  • Strong understanding of CSS Box model
  • Ability to create flexible layouts using Flexbox and Grid

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 JavaScript, HTML/CSS & React Online Test?

  • JavaScript Basics

    JavaScript Basics refers to the fundamental knowledge and understanding of the JavaScript programming language. It includes concepts such as variables, data types, operators, conditionals, loops, functions, and basic syntax. This skill is measured in the test to assess the candidate's foundational knowledge of JavaScript, which is essential for any JavaScript developer role.

  • JS ES6

    JS ES6 (ECMAScript 2015) refers to the latest version of the JavaScript language. It includes new features and syntax improvements, such as arrow functions, classes, modules, template literals, destructuring, and spread syntax. This skill is measured in the test to evaluate the candidate's proficiency in using the modern and more efficient features of JavaScript.

  • JS OOPs

    JS OOPs (Object-Oriented Programming) refers to the paradigm of organizing and structuring code using objects and classes. It involves concepts such as encapsulation, inheritance, and polymorphism. This skill is measured in the test to assess the candidate's ability to design and implement object-oriented solutions in JavaScript, which is widely used in web development.

  • Handling APIs

    Handling APIs involves the ability to interact with and consume Application Programming Interfaces (APIs). It includes making HTTP requests, parsing JSON data, handling authentication, and processing responses. This skill is measured in the test to evaluate the candidate's knowledge and practical experience in integrating web applications with external services through API interactions.

  • Asynchronous Node.js and promises

    Asynchronous Node.js refers to the ability to write asynchronous code using Node.js, a JavaScript runtime environment. It involves using callbacks, promises, and async/await to handle asynchronous operations efficiently. This skill is measured in the test to assess the candidate's proficiency in writing non-blocking and scalable JavaScript code in a Node.js environment.

  • Building components with JSX

    Building components with JSX involves creating reusable UI components using the JSX syntax, which is an extension to JavaScript commonly used in React applications. It includes concepts such as component composition, props, and state management. This skill is measured in the test to evaluate the candidate's ability to develop modular and reusable UI components using JSX in conjunction with JavaScript.

  • React Component Lifecycle

    React Component Lifecycle refers to the different stages and methods involved in the lifecycle of a React component, such as mounting, updating, and unmounting. It includes methods like componentDidMount, componentDidUpdate, and componentWillUnmount. This skill is measured in the test to assess the candidate's understanding and practical knowledge of how React components behave and interact with the DOM during their lifecycle.

  • React Hooks and functional components

    React Hooks and functional components refer to the new feature introduced in React 16.8 that allows developers to use state and other React features without writing a class. It involves using hooks such as useState, useEffect, useContext, and useRef. This skill is measured in the test to evaluate the candidate's proficiency in using hooks and functional components to build scalable and maintainable React applications.

  • CSS Box model

    CSS Box model refers to the concept of how elements are rendered and structured in CSS. It includes properties such as width, height, padding, margin, and border. This skill is measured in the test to assess the candidate's understanding of how elements are sized, positioned, and spaced in CSS, which is crucial for creating visually appealing and responsive web layouts.

  • Flexbox and Grid layouts

    Flexbox and Grid layouts are CSS layout models that provide flexible and powerful ways to arrange elements in a web page. Flexbox is a one-dimensional layout, while Grid is a two-dimensional layout. This skill is measured in the test to evaluate the candidate's ability to create complex and responsive web layouts using these modern CSS layout techniques.

  • Responsive CSS

    Responsive CSS refers to the practice of creating web pages that can adapt and adjust to different screen sizes and devices. It involves using media queries, flexible units (such as percentages and viewport units), and CSS frameworks like Bootstrap. This skill is measured in the test to assess the candidate's capability to develop web applications that provide a seamless and optimized user experience across various devices.

  • JavaScript Programming

    JavaScript Programming refers to the overall ability to write clean, efficient, and maintainable JavaScript code. It includes concepts such as code organization, error handling, debugging, performance optimization, and code documentation. This skill is measured in the test to evaluate the candidate's overall proficiency and competence in JavaScript programming, which is essential for any web development role.

  • 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 JavaScript, HTML/CSS & React Test to be based on.

    Variables
    Data Types
    Arithmetic Operations
    Conditional Statements
    Loops
    Functions
    Arrays
    Objects
    Error Handling
    Lexical Scope
    Closures
    Hoisting
    Prototypes
    Classes
    Inheritance
    ES6 Modules
    Arrow Functions
    Destructuring
    Template Literals
    Spread Operator
    Rest Parameters
    Promise Object
    Async/Await
    AJAX
    Fetch API
    JSON
    DOM Manipulation
    Event Handling
    Browser Storage
    React Components
    JSX
    Props
    State
    Lifecycle Methods
    React Hooks
    Context API
    Styling in React
    CSS Selectors
    Box Model
    Flexbox
    Grid Layout
    Media Queries
    Responsive Design
    Debugging
    Unit Testing
    Code Optimization
    Algorithm Design
    Data Structures
    Error Handling
    Code Review

What roles can I use the JavaScript, HTML/CSS & React Online Test for?

  • Full Stack Developer
  • JavaScript Developer
  • React Developer
  • Front-end Engineer

How is the JavaScript, HTML/CSS & React 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

  • Experience in creating responsive designs with CSS
  • Proficiency in JavaScript programming
  • Advanced knowledge of JavaScript frameworks and libraries
  • Experience with front-end build tools like Webpack or Babel
  • Ability to optimize web performance and optimize rendering
  • Knowledge of state management libraries such as Redux or Mobx
  • Experience with testing frameworks like Jest or Enzyme
  • Ability to integrate with third-party APIs and services
  • Understanding of version control systems like Git
  • Experience in debugging and troubleshooting complex issues
  • Strong problem-solving skills and ability to analyze requirements

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

JavaScript, HTML/CSS & React 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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