Question 1

Why is React used instead of Angular?

Accepted Answer

React is an easy to understand language. Developers and beginners can easily learn react, unlike angular. React ensures better performance as compared to other programming languages. The unidirectional flow of react easily debugs errors.

Question 2

How much time does one require to learn React?

Accepted Answer

React is an easy language and doesn't take much time to understand. Anyone can learn react in just 1-2 months. upGrad offers a free React course online that helps one understand React and the ways one can implement it in creating user interfaces, webpages, mobile apps, etc.

Question 3

Which course is best to learn React?

Accepted Answer

There are a number of courses available that will help you learn React. But nothing beats upGrad. upGrad offers a free online React course that helps one learn React easily. At the end of the course, certification is also provided to the candidates that will help getting better job opportunities in future.

Question 4

Who can learn React course?

Accepted Answer

A person who is well-equipped with JAVA and HTML can learn the React language. React is an easy language that can be learned by experienced people as well as beginners.

Question 5

What is one-way data binding in Reactjs?

Accepted Answer

ReactJS supports downstream flowing data in a single flow. The Reactjs components are hypothetically immutable, and the data stored in them can’t be changed. Hence, ReactJS only approves the data that flows in a single direction; therefore, it is known as one-way data binding. Since data will not flow in the opposite direction, it is easier to debug, and the data is less prone to error. One-way data binding makes ReactJS the best front-end library for developing highly interactive web applications. This feature is useful to ReactJS developers as a reliable source for canonical data sources.

Question 6

What are the benefits of reusable components of Reactjs?

Accepted Answer

Reactjs proves to be more powerful with reusable components because all its components are isolated. Any modification in one component will not influence the other. Reusable components decrease the complexity of ReactJS app development by making the programming process easier and more precise for the developers. Access to reusable components is the largest advantage for a startup firm willing to work on a small budget. This is because they don’t need to hire an expert to correct errors in the app.

Question 7

Why should you hire Reactjs developers?

Accepted Answer

Reactjs developers use the latest technology and trends in their projects. They own years of experience and expertise. They showcase their exceptional expertise by developing top-notch quality apps. It is challenging to handle all the web operations single-handedly. So, it becomes inevitable for a company to hire Reactjs developers who can provide support & maintenance to your website and keep it updated. You can effectively develop a custom web app by outsourcing a React developer from a reliable ReactJS development company.

Question 8

Why you may not want to use React.js for complex interactive front-end projects?

Accepted Answer

It is difficult to reuse React.js components in complex interactive web projects. React.js Virtual DOM algorithm is imprecise, and time-consuming.React.js HTML templates are neither powerful nor complete.

Question 9

Which functions are called when mounting a component in Reactjs?

Accepted Answer

When mounting a component, React calls the below built-in functions in the stated order: (i) constructor()- It denotes the first step where initial state values are set. (ii) getDerivedStateFromProps()- This method is called before rendering the element(s) in the DOM. (iii) render()- This method outputs the HTML to the DOM. (iv) componentDidMount()- This method is called after the component is rendered.

Question 10

How does React work?

Accepted Answer

Everything in React is a “component” or an “element”. The elements are generated using syntactic javascript or “JSX”. It works like declaring HTML content as variables, constants, functions, etc. JSX helps in coding a React app. Components work as the building blocks for any React app. They may contain several elements programmed to interact and behave in a specific way. Each React component has a lifecycle that can be tracked and modified throughout its three phases: Mounting, Updating, and Unmounting.

Question 11

Which brands owe their success to ReactJS?

Accepted Answer

The brands like Netflix, Instagram, Airbnb, and Yahoo owe their success to ReactJS. Reactjs’ declarative programming approach and one-way data binding help Netflix manage its huge data volumes. Reactjs fulfils Instagram’s requirement to allow web visitors to access the social platform through the one-page app. The component reusability features, code iterating, and code refactoring are useful to Airbnb in developing the internal structures of the web and mobile app.

Question 12

Why do we need to use React js?

Accepted Answer

React simplifies the development of dynamic web applications because it involves less writing and offers more capability than JavaScript. The coding process is less complex than that in other platforms. Reactjs uses a one-way data flow, allowing the developers to enclose child components in their respective parent components while developing a React project. The learning curve for Reactjs is low since most of its principles are identical to those available in JavaScript and HTML, adding a few valuable features.

Question 13

Which are the top 5 skills you must know before you learn ReactJS?

Accepted Answer

(i) HTML and CSS -All front-end developers begin their journey with HTML and CSS. Hence, before you start learning Reactjs, you must have a decent coding command in HTML and CSS. (ii) JSX (Javascript XML) & Babel -you will work with JSX which you can consider as HTML-flavored JavaScript. (iii) Fundamentals of Javascript and ES6 –Make sure you first learn the fundamentals of JavaScript and then learn the advanced version of ECMAScript5 and ECMAScript6. (iv) Package Manager (Node + Npm) –You need to learn package.json files and js files in the packages. (v) Git (version control) –It helps store your projects on GitHub, GitLab, and Bitbucket.

Question 14

What is the “Assembly of Components” in Reactjs?

Accepted Answer

One of the distinguishing features of ReactJS is component-based user interface development. Any React app is an assembly of multiple components. All these can fall into categories -reusable components, core ReactJS components, or app-specific custom components. With “Assembly of Components”, React allows you to create standalone isolated components for use in the apps. This feature improves reusability, offers faster development, and guarantees lesser UI defects.

Question 15

What is React Virtual DOM?

Accepted Answer

React Virtual DOM’s role is quite notable in front-end development. Virtual DOM represents an in-memory copy of the original DOM created by the browser. React Virtual DOM provides a better user experience and allows app developers to work faster. Modifying the UI demands updating the real DOM. But frequently updating the real DOM can make the UI sluggish and leads to costly computations at the browser level. React Virtual DOM solves all these problems.

Question 16

What is State Management in Reactjs?

Accepted Answer

Reactjs uses one of the most sophisticated state management libraries, i.e., Redux. You can manage the state of the components for developing small apps that contain only a few components. But as the application grows, managing the state in individual components becomes challenging. Redux is a state management library that equips developers with the ability to retrieve and set the state from components to the state store. Moreover, state management helps developers to write scalable and maintainable code.

Question 17

What is Automated Batching in Reactjs?

Accepted Answer

Automatic batching was implemented as one of the important features in React 18. ReactJS now offers out-of-the-box batching for intervals, timeouts, state updates, event handlers, and asynchronous operations with this feature. Before React 18, batching the state changes was allowed but with complex app-level coding. Automatic batching makes sure a lot of app-level development for batching is not required during an asynchronous state change.

Question 18

What are the commonly faced problems in Reactjs?

Accepted Answer

(i) The component name doesn’t start with a capital letter, so the component use is treated as a built-in element. (ii)The PropTypes object is removed from Reactjs. (iii) Within a Javascript class body, you can only define properties and methods using limited syntax. (iv) Once the web server continues running successfully, it owns control over that port. So, you can’t use the same port for other tasks. (v) Confusing curly brackets with parentheses. (vi) Doesn’t use the right capitalisation of API methods and properties. (vii) Developers get confused with State Object and Instance Properties. (viii) The import/export feature is not fully supported in the latest Nod and modern browsers.

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