Basic Level – ReactJS Interview Questions
- What are the features of React? …
- What is JSX? …
- Can web browsers read JSX directly? …
- What is the virtual DOM? …
- Why use React instead of other frameworks, like Angular? …
- What is the difference between the ES6 and ES5 standards? …
- How do you create a React app? …
- What is an event in React?
Indeed, How do you prepare for a React interview?
Then, What are the main topics in ReactJS?
- React State vs Props.
- React Constructor.
- React Component API.
- Component Life Cycle.
- React Forms.
- Controlled vs Uncontrolled.
- React Events.
- Conditional Rendering.
What is ReactJS mainly used for? React JS is a JavaScript library used in web development to build interactive elements on websites.
In the same way What are hooks in react JS? Hooks are a new addition in React 16.8. They let you use state and other React features without writing a class. Hooks are backwards-compatible.
What are the biggest limitations of React?
Disadvantage of ReactJS
- The high pace of development. The high pace of development has an advantage and disadvantage both. …
- Poor Documentation. It is another cons which are common for constantly updating technologies. …
- View Part. ReactJS Covers only the UI Layers of the app and nothing else. …
- JSX as a barrier.
What is use of Redux in react JS?
React Redux is the official React binding for Redux. It allows React components to read data from a Redux Store, and dispatch Actions to the Store to update data. Redux helps apps to scale by providing a sensible way to manage state through a unidirectional data flow model. React Redux is conceptually simple.
What is JSX in React?
JSX stands for JavaScript XML. JSX allows us to write HTML in React. JSX makes it easier to write and add HTML in React.
What is render in react JS?
React renders HTML to the web page by using a function called render(). The purpose of the function is to display the specified HTML code inside the specified HTML element. In the render() method, we can read props and state and return our JSX code to the root component of our app.
What is props in react JS?
Props are arguments passed into React components. Props are passed to components via HTML attributes. props stands for properties.
What is life cycle of react JS?
The three phases are: Mounting, Updating, and Unmounting.
What is Babel in React?
Babel is a JavaScript compiler that includes the ability to compile JSX into regular JavaScript.
What is middleware in React?
Middleware allows for side effects to be run without blocking state updates. We can run side effects (like API requests) in response to a specific action, or in response to every action that is dispatched (like logging). There can be numerous middleware that an action runs through before ending in a reducer.
What is Dom in React?
DOM: DOM stands for ‘Document Object Model‘. In simple terms, it is a structured representation of the HTML elements that are present in a webpage or web-app. DOM represents the entire UI of your application.
What is difference between React and Redux?
Redux manages state and state transformations and is often used with React, but React has its own concept of state. When using these libraries, it’s good to know which to use when. Even if you choose to use Redux in your project, you will still need to make decisions on how much of your data is stored in Redux.
What is Babel in react JS?
Babel is a toolchain that is mainly used to convert ECMAScript 2015+ code into a backwards compatible version of JavaScript in current and older browsers or environments.
What is triple dot in react JS?
(three dots in JavaScript) is called the Spread Syntax or Spread Operator. This allows an iterable such as an array expression or string to be expanded or an object expression to be expanded wherever placed.
What is lazy loading in React?
In essence, lazy loading means that a component or a part of code must get loaded when it is required. It is also referred to as code splitting and data fetching . Talking about React specifically, it bundles the complete code and deploys all of it at the same time.
What is DOM in React?
DOM: DOM stands for ‘Document Object Model‘. In simple terms, it is a structured representation of the HTML elements that are present in a webpage or web-app. DOM represents the entire UI of your application.
Does React use HTML?
With React, we write HTML using JavaScript. We rely on the power of JavaScript to generate HTML that depends on some data, rather than enhancing HTML to make it work with that data. Enhancing HTML is what other JavaScript frameworks usually do.
What is Axios in React?
Axios is a lightweight HTTP client based on the $http service within Angular. js v1. x and is similar to the native JavaScript Fetch API. Axios is promise-based, which gives you the ability to take advantage of JavaScript’s async and await for more readable asynchronous code.
What is mount and unmount React?
The main job of React is to figure out how to modify the DOM to match what the components want to be rendered on the screen. React does so by “mounting” (adding nodes to the DOM), “unmounting” (removing them from the DOM), and “updating” (making changes to nodes already in the DOM).
What is props and state in React?
In a React component, props are variables passed to it by its parent component. State on the other hand is still variables, but directly initialized and managed by the component. The state can be initialized by props.
What is Webpack in react JS?
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 (spriting) through the use of plugins.
What is Webpack and Babel in React?
@babel /preset-react: compiles the React code into ES5 code. d. babel-loader: a Webpack helper that transforms your JavaScript dependencies with Babel (i.e. will transform the import statements into require ones)
What is Webpack?
Webpack is a tool that lets you compile JavaScript modules, also known as module bundler. Given a large number of files, it generates a single file (or a few files) that run your app. It can perform many operations: helps you bundle your resources.
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