A JavaScript package called React is used to create user interfaces. Applications using only one page can be created using React. Reusable UI components can be made using React.

For creating reusable UI components, ReactJS is a declarative, effective, and adaptable JavaScript toolkit. It is a front-end component-based open-source library that exclusively handles the application’s view layer. Initially created and maintained by Facebook, it was eventually incorporated into services like WhatsApp and Instagram. Visit the Edureify website to learn more about React JS.

1) Describe React.

Answer:- In 2011, Facebook created React, an open-source front-end JavaScript toolkit that is declarative, effective, and flexible. For creating reusable UI components, particularly for single-page applications, it uses the component-based method. It is utilised to create interactive view layers for both online and mobile applications. Jordan Walke, a software engineer at Facebook, developed it. It was first utilised in 2011 in Facebook’s News Feed section and then appeared in applications like WhatsApp and Instagram.

2) What characteristics does React have?

The greatest framework for web developers is React, which is quickly gaining popularity. React’s primary characteristics are:

One-way Data Binding Virtual DOM Simplicity Performance JSX Components.

3)When was React originally made available?

Answer:- React was first made available in March 2013.

4) Identify the two biggest drawbacks of React.

Answer:- React integration with MVC frameworks like Rails calls for intricate settings.

Users of React must understand how the MVC framework and user interface are integrated.

5) What purposes do React Fragments serve?

Answer:- The correct answer is that React fragments are a unique feature that enable you to write group child elements or components without actually generating a node in the DOM.

The fragment syntax resembles an empty set of tags with the symbol > or tags with the label React.

To put it another way, there are occasions when we need to group several React elements under a single parent, but we don’t want to use a standard HTML element like a div.

6) What Does the React Flux Concept Mean?

Answer: Facebook frequently creates client-side web applications using the flux architecture approach. It is not a library or a framework. It is merely a fresh approach to design that supports Unidirectional Data Flow and React.

7) What does Redux mean in React?

Answer:- Redux is a front-end development library. It is a state container for JavaScript applications and ought to be used to manage the state of the application. An application created with Redux can be tested and used in a variety of settings.

8) What does Redux’s “Store” function do?

Redux offers a feature called “Store” that enables you to save all of the application’s state in one location. Consequently, each of its constituent States is constant.

9)What does a Redux action entail?

It is a function that produces an action object, to be precise. The action object is where the action-type and action data are always kept. Between the Store and the software programme, actions can send data. The operations generate all of the data that the Store retrieves. If you want to learn more about redux and reactive JS, go to the Edureify website.

10) What are the key components of React?

Here are several crucial React features.

enables the use of third-party libraries

Expeditious Quicker Development

Composability and simplicity

completely backed by Facebook.

One-way data binding for code stability

Components for React

11) What does “stateless components” mean?

The correct response is that stateless components are purely functional and only render the DOM using the properties that are sent to them.

12)Describe React Router.

React Router is a routing library that enables you to add additional screen flows to your application and maintains synchronisation between the URL and what is displayed on the page.

13) Which React ecosystem animation packages are the most well-liked?

Answer:- The React ecosystem’s most widely used animation packages are

Question 14) What exactly is Jest?.

In response, Jest is a Jasmine-based JavaScript unit testing framework developed by Facebook. It provides a jsdom environment and automated mock generation. Additionally, it serves as a testing element.

Qsn 15:- What does a dispatcher do?

A dispatcher is the main hub of the programme, from which you may accept actions and disseminate payload to callbacks that have been registered.

Qsn 16:- What does the callback function mean? What does it accomplish?

The component should be re-rendered after setState has completed, at which point a callback function should be triggered.

Because set State is asynchronous, a second callback method is required.

17) Describe what high order component means.

An advanced method of reusing component logic is called a higher-order component, or HOC for short. They are a pattern that comes out of the compositional structure of React but are not a part of the React API.

18) What does the Presentational section entail?

A presentational portion is a section that enables HTML rendering. In markup, the segment’s capacity is presentational.

19) What do React.js Props do?

Props refers to properties, which is a way of passing data from parent to child. We can say that props are just a  communication channel between components. It is always moving from parent to child.

20) In React, what purpose does a super keyword serve?

The super keyword enables you to call and access functions on the parent of an object.

21) What does the JavaScript catchphrase yield mean?

The yield catchphrase, which is used to pause and resume generator operations, is the correct response.

22)Name two different types of React components.

Answer:- There are two categories of responding elements:

  • Function component 
  • Class component 

23) What does React JS’s concept of synthetic events mean?

The native event of the browser is wrapped with a type of object called a synthetic event across all browsers. Additionally, it facilitates the integration of different browser actions into the signal API.

24)What is React State, exactly?

The answer is that an object determines how a particular component renders and behaves. A React component’s state contains all of the information that can be modified during its lifespan.

25) How does React.js refresh the state?

Answer: A component’s state may be modified directly or indirectly.

26) Can you describe how the arrow function in React is used?

Answer: When supplied as a callback, the arrow function aids with bug behaviour prediction. As a result, it completely eliminates bugs brought on by this.

27) What are the React lifecycle steps?

React js’s key lifecycle steps are as follows:

  • Initialization
  • Property and state updates
  • Destruction is the stage of React’s lifecycle.

28)What is the primary distinction between Pros and States?

The major distinction between the two is that the former is immutable, whilst the latter is malleable.

29) What exactly are React’s “pure components”?

The fastest command that can replace any component with just a render is “pure components” (). It aids in improving the coding application’s simplicity.

30) In React, what type of data controls a segment?

State and Props are the two major types of information that regulate a section.

  • State: We must use State in order to use state information that will change.
  • Props: A parent sets and maintains props for the duration of a part’s life.

31)How does “create-react-app” work?

The command-line utility “make-react-app” enables you to create a single, simple react application.

32) Describe the function of “key” in a react list.

Using keys, you can give each list entry a reliable identification. The keys ought to be special.

33) What advantages do kids have?

Answer:- Children’s props are employed to transfer properties from one component to another. You can get to it by utilising“props. kids”

34) What do error boundaries mean?

Answer:- You can find Javascript faults everywhere in the child components by using error boundaries. They are mostly used to log errors and display a fallback user interface.

35)What purpose do empty tags > serve?

Answer: Declaring fragments in React uses empty tags.

36) What is the strict mode?

The answer is that you can perform checks and issue warnings for react components in strict mode. Only development builds support it. Without creating a visible UI, it aids in highlighting the problems.

37)What do React Portals do? 37

The answer is that you can render children into DOM nodes using Portal. It uses the CreatePortalmethod to do it.

38)What is Context? 38

Answer: Using the react component tree and react context, you may transmit data. It enables global data sharing between different react components.

39) What function does Webpack serve?

Webpack is a module builder, to be precise. It primarily operates throughout the creation process.

40)What does React js’ Babel mean?

The most recent JavaScript, such as ES6, and ES7, are converted into the more traditional ES5 JavaScript, which is supported by the majority of browsers, by the JavaScript compiler Babel.

41) How can JSX files be read by a browser?

The JSX file should be changed using a JSX transformer like Babel and then delivered back to the browser if you want the browser to read JSX.

42) What are the main drawbacks of React’s MVC architecture?

The following are the principal difficulties you’ll deal with when handling the MVC architecture.

DOM handling is very pricey.

Applications were frequently sluggish and ineffective.

Circular functions have caused a complicated model to be built around models and concepts.

43) When there are multiple lines of expression, what can be done?

The only choice you have at that point is a multi-line JSX expression.

44) How much has been reduced?

The reduction is a state management application method.

45) What does “synthetic events” mean?

Answer:- It is a cross-browser wrapper for the native event of the browser. These events have interfaces for preventDefault and stopPropagation() (). For further details on any subject relating to coding, see the Eduriefy website.

46) When should the function element employ top-class elements?

The best elements should be used if your element has a stage or lifetime cycle.

47)How is it possible to share an element during parsing?

We can share the info using the State, in response.

48) What does reconciliation mean?

The rest will compare the rendered element with the previously rendered DOM and update the actual DOM if necessary when a component’s state or props change. Reconciliation is the name given to this procedure.

49) If you don’t want to use the setState() function, how can you re-render a component?

The force update() function can be used to render any component again.

50) Is react capable of updating props?

Because they are read-only, react js properties cannot be updated. Additionally, you cannot change any props that were given to you by your parents.


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