Top 5 Interview Questions For Junior React JS Developers


Interview questions for Junior react JS developers will appear unsuitable for your potential employee if they do not cut across certain important areas. Remember, you do not want to create the wrong first impression with your employee.  


This article outlines the most important Interview questions for junior react JS developers and explains the basic qualifications of a Junior react JS developer. 


First tip, Junior react JS developers need extra credit; the tag “junior” on their title doesn't mean they are entirely newbies. These guys have astounding abilities, and with the right motivation, a Junior react JS developer might be the only person you need to move your organization one step forward. 


A Junior React JS Developer

React is a special library for JavaScript. 


Great companies like Uber, Facebook, AirBnB, Netflix, Instagram, and Amazon have a team of developers who use react for almost every programming function on their websites. This means that the world is in daily need of react developers. 


Having the best junior react developers work on your project sounds like a privilege, but you can keep this privilege consistent, beginning with the right interview questions.


Junior React developers will have to use their knowledge of JavaScript, CSS, HTML, and other web scripting languages to integrate ReactJS and other JavaScript library functions into front-end applications or websites. 


Junior developers work with quality assurance specialists to test codes before an application or website goes live. They are usually part of a team of developers, programmers, and designers directed by a project manager working closely with the company or clients to implement website design tasks.


The basic functions of a Junior Developer include writing and maintaining the code of computer applications. They have to learn to write basic code, correct the errors that can arise, and compile user data. Junior Developers also have to deal with requests from the Senior Developer, supporting all the software design and coding functions.


Skills To Expect From A Junior React Js Developer

Before you proceed to the interview session for your Junior react JS developer, you should look out for important skill sets in them. If your potential developer employee has these skills, you are on your way to hiring the right person for your organization. 


Every Junior react Js developer should possess the following skills:


  1. Fundamentals of JavaScript

  2.  HTML and CSS

  3. Node+NPM

  4. Javascript ES6

  5. Redux

  6. JSX

  7. GIT


1. Fundamentals of JavaScript

JavaScript is basic for ReactJS developers. Junior react JS developers should possess sufficient knowledge of JavaScript concepts like:


  • Surrounding code structure. 

  • Variables. 

  • Data types. 

  • Operators. 

  • Functions. 

  • Loops. 

  • switch statements. 

  • Objects. 

  • Primitives. 

  • Boolean. 

  • Array. 

It is important that Junior developers have practical knowledge of these principles as these fundamentals of JavaScript would be required in building codes in ReactJS. 


If they satisfy the fundamental knowledge requirements of Javascript, then their React JS developer skills would be excellent.


2. HTML and CSS

Hands-on skills with HTML and CSS are core skills that every junior developer should possess. 


Knowledge of these client-side technologies and important react developer tools proves that they can create and work with advanced, visually-aesthetic, and highly intuitive user interfaces (UIs). 


The candidate should at least know how to work with and write HTML tags and CSS selectors. They should also have an understanding of the box model. 

Skills like CSS reset, implementing responsive web principles, and reverting to border-box can increase their chances of getting hired.


3. Node + npm

While React caters to front-end development, Node takes care of back-end development. The MERN (MongoDB, Express, React, Node) stack is a perfect example of such a full-stack environment. 


You should also consider that developers can run React codes directly in the Node environment and vice versa, which further enhances their interoperability, increasing the need for react developers to be skilled in Node.


Furthermore, with React featuring on the server-side and client-side script, knowing Node will ensure good performance.  


Also, ensure that candidates possess a detailed understanding of the NPM (Node Packet Manager) registry. 


This registry can help developers unlock more value within the React library and app packages.


4. JavaScript ES6

In addition to the above-listed skills, React developers should possess a solid understanding of ES6 (ECMAScript 2015 or ECMAScript 6). 


This is a newer version of JavaScript. It enables the developer to build and maintain in-demand web applications.


ES6 skills include:


  • Scoping variables. 

  • Array methods.

  • Arrow functions.

  • DOM manipulation.

  • Event handling.

  • High-order functions.

  • Call-back functions.

  •  ‘this’ keyword.

Researchers have observed that ES6 looks like an advancement of the fundamentals of JavaScript. 


These React JS developer skills may be different but should be treated as complementary.


5. Redux

Understanding and working with Redux is one of the most crucial ReactJS developer skills. This is due to the fact that asynchronous state updates are one of the weakest links of React development. 


Developers use Redux for state management through the lens of scalability. By adopting and applying the principles of functional programming and immutability, Redux helps the developer produce apps that behave consistently, are easy to test, and operate similarly in different environments.


6. JSX (JavaScript XML)

ReactJS developers with JSX skills can effortlessly code and incorporate HTML/XML elements in React. 


React developers proficient with JSX can build applications that utilize React APIs – an otherwise tedious task. 


JSX helps enhance app scalability – without complicating the code. However, Babel skills could substitute for JSX, depending on your requirement.


7. Git

GIT skills allow ReactJS developers to store projects on centralized version control systems like GitHub, GitLab, and BitBucket. While stored, developers can make necessary modifications to the code using commands like push, pull, comment, add, etc. 


5 Strategic Interview Questions for Junior React JS Developers

Junior react Js developers with the above skills will find these questions challenging enough to make a great first impression and easy enough to ace the interview.


The following are interview questions for Junior react JS developers:


1. What Are React Components? Why Are Components So Important To React?


This will be easy if the candidate has basic experience using React. 


Components are the building materials used in React to create websites and application UI. 


Components are important to React because they break a UI down into reusable parts, which allows React to render each UI component as needed. Components can be attributed to speed and performance efficiency in react.


2. State the Difference Between Props And State?


This is a granular technical question in react, and candidates with good experience with ReactJs expect this.


“State” describes a changeable default data value in a React component. It is subject to change with time. 


On the other hand, “Props” (or properties) are us to show the way a React component is configured. Props do not change.

Simply put, the state is changeable based on user actions and time, while props are not.


3. Choose One Component Lifecycle Method You’ve Used On A Project. 


Tip: If you’ve worked with React, you know that a react component’s lifecycle includes its birth- when the component is created and mounted on the project’s DOM, its growth-  when the component is updated over time, and its death when the component is unmounted from the project’s DOM.


A component lifecycle method refers to the functions a component can execute during specific lifestyle phases. 


4. When Would You Use A Class Component Over A Functional Component?


React primarily uses class components and functional components. 


Functional components are the most basic kind of React components. The component’s props define them.


On the other hand, class components are more complicated React components that allow developers to execute and manage the component lifecycle.


5. What Are React Events?


Events are reactions triggered by specific user actions like clicking on a UI button, hovering a mouse over a UI object, using keyboard commands with the UI, etc.


The Droomwork Hack

Getting the right interview questions for Junior React JS developers will inform your employee's efficiency; it is, therefore, necessary to be as meticulous as possible with this. Droomwork is offering to help you.


Droomwork has built-in skill-level tests for every developer level. Our interactive skill-based tests ensure that developers answer questions based on their level of expertise and industry trends.


Our system ensures efficiency and speed and employs the right developers. 


Save yourself the stress of sourcing, interviewing, and onboarding on-demand Junior react js developers by hiring on Droomwork. 





Droomwork is the hub that houses the best freelancers, startups, HR, and businesses, the infrastructure, brings interconnectivity that matches everyone's needs.


Get qualified and reliable developers & designers around the world ready to scale your project.



Stay conneced with Droomwork on your social accounts.

© Copyright 2023 Droomwork. All rights reserved.