Top 10 React JS Interview Questions

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ReactJS is an open-source, component-based front end library responsible only for the view layer of the application. It was developed by Facebook in 2013.

React Interview Questions - Education Funda
React JS - Education Funda

Some Important Notes

Virtual DOM

The DOM represents a document with a logical tree. Each branch of the tree ends in a node, and each node contains objects. DOM methods allow programmatic access to the tree.

Imagine that you have an application and whenever there’s a state change, you want to update only the parts of your DOM tree that depend on those changes. You don’t want to re-render your whole UI from scratch because it would cost a lot, performance-wise, and the UX would be bad.

React works with a feature called virtual DOM, a virtual representation of the real DOM tree. It’s just a tree data structure of plain JavaScript objects that is kept synced in memory. Rendering the virtual DOM is faster because it will never be rendered to the user, it will only live in memory.

Class Component vs Functional Component

Class component is an react js way of use component, in which we create an Class giving name of it and extends the Components whereas Functional component is an ES6 way of component in which we create const variable and we use arrow function in it.

Let's check the top 10 reactjs interview questions in below video:


I hope these questions will help you to crack react js interview easily.

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