Common React JS Interview Questions + Tips for Answering

React JS Interview Questions

ReactJS is termed as a methodology in which the development and operations join hands in collaboration to complete, to attain the desired organization goals. This culture is obtained by organizations in order to achieve their desired marketplace in the sector. This process enables the teams to obtain higher returns from limited resources by sharing ideas and skill sets. Due to this reason only, the organization is able to increase its productivity. In this case the teams combine efforts in their sectors and allow the company to develop the software by fulfilling the client requirements as well as the customer feedbacks. Due to this reason, the products flourish in the market as it fulfills all the requirements and demands while maintaining profit for the organization.

JavaScript certification is a popular platform for coding and has a worldwide huge fan base. Facebook started an online open-sourced library in order to help the developers along with few other developers that provided assistance in front end coding. The interviews one needs to clear for mastering ReactJS includes a set of questions.

• What is React?

A. A Facebook owned JavaScript library. It has a user interface including components and UI elements. These can be used for front end coding for several applications and software development. It is an open-source library.

• Mention the prominent features of React.

– Replacement of real DOM by virtual one
– The rendering style of React is server sided.
– The data binding or data flow of React is uni – directional.

• Can you count some of the limitations of React?

A. Coding and JavaScript are not completely suitable on React platform. The elements, components and navigation in the user interface are not the cup of tea for beginners and takes a bit of practice to master or at least understand. The vast library is not everyone’s cup of tea. The utilization of JSX and inline emulating makes coding with React a tad bit more difficult in comparison to other such tools.

• What exactly is meant by the JSX?

A. JSX is nothing but the acronym of the JavaScript XML. It’s a file that is utilized by the React in order to make HTML easier along with the expressiveness of JavaScript and HTML template syntax.

• Define Virtual DOM.

A. It is a JavaScript object that is a clone of the real DOM used for listing elements, objects, attributes and properties. The changes made to them reflect accordingly. But the difference is that only the final changes reflect after saving and not the intermediate ones unlike a real DOM.

• Why are JSX unreadable by browsers?

A. Because they are not proper JavaScript objects and need transformation into one.

• Differentiate between Angular and React.

A. While React has server side rendering and uses virtual DOM, Angular has client side rendering and uses real DOM.

• Explain the statement that Everything is a component in React.

A. Every UI is split into packages of components. Thus everything on React is just a component.

• Describe the purpose of render().

A. It is used to return a single representative value of the native DOM component.

• Define Props.

A. Props are the properties of objects stored in React.

• Why Arrow is used?

A. These are used as syntax(=>).

• Mention different phases of React component’s lifecycle.

A. Initial rendering, updating and unmounting phases.

• Name some lifecycle methods.

A. ComponentDidMount(), shouldComponentUpdate(), componentDidUpdate(), etc.

Basically, the class is used to read all the data which have been collected. Java scanner is built into the java until package so that in future any time the external librarian can read them. Scanner will read only if the text are from standard input or else it will not read the text if those not from the standard input. It is really very important to know how to get user input in Java. This text will is required to return back to the main program so that the data can be store without having any kind of leakage of data or else it may get manipulated by any wrong hands. In further we will discuss that how to utilize the java scanner to receive user input.


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