React & Redux interview questions. Answered by me.

ReactJS logo intercrossed with Redux logo

1- What is React?

2- Explain the virtual DOM.

  • It doesn’t re-render the entire DOM, only the changed nodes
  • It doesn’t cause a performance drop
  • changing and creating the virtual DOM is cheap because it is very fast and it will never be rendered on the screen, this is why it is useful for comparison instead of using the real DOM.

3-What are pure functional Components?

5- Which feature can we use to cause a component to render only when its ID changes?

6- List some of the major advantages of React.

  • It’s is a library, not a framework, which means it provides you with utilities to help YOU WRITE THE CODE, unlike frameworks it doesn’t write the code for you, which is important to avoid inversion of control.
  • Virtual DOM, which is important to avoid unnecessary re-rendering and re-painting of the entire dom because of minor changes.
  • Reusable Component-based pattern, which allows you to efficiently organize your code and connect components together in a predictable way.
  • JSX (JavaScript XML) which allows us to write HTML inside of JavaScript.
  • React hooks and component lifecycle, which allows us to control how our component should behave during its lifetime using various hooks.

7- What are the limitations of React?

  • Deprecated features that people got used to.
  • Deprecated documentation about deprecated methods.
  • Not enough recent documentation to keep up with the new features.

8- What is JSX?

9- Why can’t browsers read JSX?

10- What do you understand from “In React, everything is a component.”?

11- Explain the purpose of render() in React.

12- What is Props?

13- What is a state in React and how is it used?

  • It is used to render data to the DOM
  • It is used to be passed down as props to a child component
  • It is used to be integrated with a method or a function

14- What is an event in React?

15- What is Redux?

16- In Redux, what do you understand by “Single source of truth”?

17- Explain the role of the Reducer.

18- What is the significance of Store in Redux?




Front-end web developer and graduate student from Microverse.

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Abdo Amin

Abdo Amin

Front-end web developer and graduate student from Microverse.

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