ReactJS Interview Questions

Hey guys,

      Below are some important interview questions with answers, hope you all like them.
For any improvement/suggestions use the comment box below:

1.What is React?

    ReactJS is an open-source, declarative, flexible front-end javascript library for building reusable user interfaces.
    ReactJS is not a framework, it’s just a library that includes configuration data, documentation, help data, message templates, pre-written code and subroutines, classes, values, or type specifications.

2.What are the Features of React?

1.JSX: JSX stands for Javascript XML,It’s a Javascript syntax Extension for ReactJS.It’s not compulsory to use JSX but it’s recommended for ReactJS.
 React uses the feature called Components, where each component has its own logic & controls. Creating multiple components makes use of them at multiple locations in large-scale projects, making React more popular.
3.One-way Data Binding: React flows unidirectional-data flow or one-way data binding which gives good control throughout the application.
4.Virtual DOM: React makes use of the virtual DOM concept, here react has its own DOM called Virtual DOM & every time any changes are done in the application, they are affected in React DOM only. the real DOM will update only the things that have actually changed. This makes the application faster & there is no wastage of memory.
5.Simplicity: React makes use of components for code reusability. It’s simple & easy to learn.
6.Performance: React uses virtual DOM concept which makes it very faster & memory efficient automatically increasing the performance of the application.

3.What are the Advantages & Limitations of React?


1.Easy to Learn & Use: ReactJS comes with good resources such as documentation & tutorials hence it’s easy to use. Any developer from a javascript background can easily start working on react applications.

2.Reusable Components: React creates component-based applications i.e everything in react is in the form of components. This makes reusability of code in large-scale applications.

3.Performance Enhancement: React makes use of the virtual DOM concept which makes react faster & less memory consuming.

4.Use of Javascript library: React makes use of Javascript Library. The JavaScript library provides more flexibility to web developers to choose the way they want.


1.Continues Updates: React Environment changes so fast that developers need to get updated themselves every day. Developers need to be updated with their skills and learn new ways of doing things.

2.Poor Documentation: React is updating so fastly that every new feature has to be documented by creators of React. To overcome this, developers write instructions on their own with the new releases and tools in their current projects.

3.Use of JSX: React makes use of JSX i.e HTML with javascript but not all developers are comfortable with JSX.

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