React Interview questions…

These basics you should know if you are a react developer or if you want to be a react developer. These theoretical concepts may be asked in interview as well.

1. Webpack | What is webpack?

Webpack is a module bundler for javascript applications. Webpack recursively builds every module in your application, then packs all those modules into a small number of bundles.

Webpack is a free and open-source module bundler for JavaScript. It is made primarily for JavaScript, but it can transform front-end assets such as HTML, CSS, and images if the corresponding loaders are included. Webpack takes modules with dependencies and generates static assets representing those modules.

Webpack is a popular module bundling system built on top of Node. js. It can handle not only combination and minification of JavaScript and CSS files, but also other assets such as image files through the use of plugins.

2. Babel

Babel is a JavaScript compiler that transform the latest JavaScript features, which are not understandable to every browser, into a backward compatible version of JavaScript in current and older browsers or environments.

• Web browsers cannot read JSX directly. This is because they are built to only read regular JS objects and JSX is not a regular JavaScript object
• For a web browser to read a JSX file, the file needs to be transformed into a regular JavaScript object. For this, we use Babel

3. JSX | What is JSX in react?

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JSX is a syntactical extension to JavaScript. JSX stands for JavaScript XML. JSX allows us to write HTML in React. JSX makes it easier to write and add HTML in React.

4. Virtual DOM

React keeps a lightweight representation of the real DOM in the memory, and that is known as the virtual DOM. When the state of an object changes, virtual DOM changes only that object in the real DOM, rather than updating all the objects.

5. Components in React

There are 2 types of components. Class components and functional components.

Functional Components Syntax:

const MyFunComponent =()=> {
  return <h2>Hi, This is a functional component!</h2>;
}

Class Components Syntax:

class MyClassComponnet extends React.Component {
  render() {
    return <h2>Hi, This is a class component!</h2>;
  }
}

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