Frequently Asked React.Js Interview Questions and Answers to Secure a Job at the Top IT Company in Surat

Needless to say that amid an overly intensified market, an app should have very unique as well as engaging UI to attract more users than other apps. However, app development companies and app owners generally give the cold shoulder to the UI of the app as they are using only futuristic features of the app as the marketing asset. But this is a poor approach to market an app and build an initial user base. Users always prefer an app that makes them feel that they are not only ‘using’, but ‘looking’ at the very well-engineered and well-designed app. This means the UI of the app is as important as the futuristic features of the app. 

There was a time when developers didn’t have more options to design an appealing interface of the app. But as users started selecting the app based on its UI and user experience, app owners started asking app development companies to satisfy users’ needs in the best possible way. 

Facebook launched React.Js in 2013 and it was the aftermath of rising demand for the very easy and efficient development technology to build user interfaces of mobile apps without fighting an uphill battle. Currently, all mobile app development companies are using React.Js to build interacting and flashy UI of mobile apps. And for that, they are actively hiring more and more React.Js developers. 

What is React.Js?  

 

React.Js is the JavaScript library which is very purposeful to build user interfaces of mobile apps. It was launched by Facebook and a community of individual developers and companies. 

Not only mobile app, but React.Js can also be useful to develop Single-Page-Application. React.Js is the best choice when there is a requirement to fetch rapidly changing data that needs to be recorded. Components are the key elements of the React.Js. A Component is nothing but the self-contained module which renders output. A developer can easily write the code of button and input field as the Components. 

Let’s understand the use of Components through an example. 

Suppose, you want to build a form using React.Js. For that, you have to write each interface element like input field, label or button as the React.Js components. Not only this but you also have to write the higher-level components which define the structure of the form itself. And these higher-level components contain the already written components of the input field, label or button. 

The popularity of React.Js and market demand for React.Js developers 

 

The following image depicts that the popularity of React.Js has skyrocketed in recent times and even surpassed its biggest rival, Angular.Js. 

As an upshot of the rising popularity of the React.Js, market demand for React.Js developers is also increasing. Refer the following image to know how easily a React.Js developer can secure a good job. 

Frequently asked React.Js interview questions and answers 

 

The following are the most frequently asked React.Js interview questions and answers which you should read before entering the interview room. 

Question 1: What are the differences between React.Js and Angular.Js? 

Answer: 

  • Angular is the framework, while React.Js is the JavaScript library. 
  • To update the Real DOM (Document Object Model), Angular uses two-directional data flow process. Whereas, React.Js updates virtual DOM and uses only one-directional data flow message. 
  • React can be used along with other programming libraries. Angular doesn’t depend on other programming libraries as it is the complete solution itself. 
  • Angular.Js can delay project delivery as the code of it is a bit complex. 

Question 2: What is the life-cycle of the React.Js components? 

Answer: 

A Component has two types. One is the High-Level Component and the other is the Low-Level Component. 

High-Level Component Life Cycle: 

  • Initialization
  • State/Property Updates
  • Destruction

Low-Level Component Life Cycle: 

  • Initialization 
  • Update 
  • Destruction 

Question 3: What is the Flux? 

Answer: 

Flux is the architectural pattern that enables unidirectional data flow. When we use Flux, multiple components can interact with derived data at the same time. However, Flux is the generic pattern and it is not specific to React Applications.

Question 4: What is the use of Keys in React.Js? 

Answer: 

To find out unique VDOM Elements with their corresponding data, Keys are used. 

Question 5: What is the use of refs in React.Js? 

Answer: 

As <li ref=“XYZ”/>, Ref is generally added to an attribute React.createElement(). The ref is useful to get simple access to DOM Element which is represented by React Element. 

Question 6: List out some limitations of React.Js. 

Answer: 

  • React.Js is not a framework (a whole ecosystem), but it is just JavaScript Library.
  • The Library of React.Js is large and complex. 
  • Google and other search engines can’t index React.Js application properly. 
  • React.Js comes with poor documentation. 

Question 7: What is JSX?  

Answer:

JSX stands for JavaScript XML and it allows developers to write HTML in React.Js. It converts HTML tags into elements of React.Js. When developers use JSX, they don’t have to use createElement() and appendChild() methods to place HTML elements in DOM. 

With JSX: 

const myelement = <h1>I Love JSX!</h1>;

ReactDOM.render(myelement, document.getElementById(‘root’));

Without JSX: 

const myelement = React.createElement(‘h1’, {}, ‘I do not use JSX!’);

ReactDOM.render(myelement, document.getElementById(‘root’));

Question 8: What are the Props in React.Js? 

Answer: 

Props in React.Js are nothing but properties that are read-only components. These Props components are always passed down from parents to child components. With this, we can maintain a unidirectional data flow. 

Question 9: How to modularize code in React.Js? 

Answer: A code is called modular when it is separated into different modules. In React.Js, we can modularize the code by using two properties – export and import. 

Question 10: If we hire you, for which purposes you will use React.Js and why? 

Answer: 

React.Js is very serviceable to build UI of the mobile app. However, we can also use React.Js to develop a dynamic page that rewrites the current page rather than loading the entire page from the server. 

There are many reasons to use React.Js. High productivity, easy maintenance, faster rendering, helpful developer toolset, and stable code are the main reasons. 

React.Js job in Surat 

 

Coruscate is the top IT company in Surat which has delivered 200+ projects to global clients. With 100+ well-schooled developers and designers, we are disrupting FinTech and Micro-Mobility industries. 

Currently, we are hiring React.Js developers at a top IT company in Surat – Coruscate Solutions. The underlying purpose to open React.Js job vacancy in Surat is to make our team stronger to accomplish several challenging tasks. So, if you are looking for React.Js job in Surat to work on large-scale projects of global clients, please check requirements and apply online from here.  

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