Q2431. What is babel?
Babel is a JavaScript transpiler to convert ECMAScript 2015+ code into a backwards compatible version of JavaScript in current and older browsers or environments. Some of...
Technical Question Bank · Peer-Reviewed
Job Interview Questions and Answers Directory
Search and filter frequently asked interview questions across technical, programming, and behavioral domains. Tailor your interview preparation by difficulty for freshers or experienced developers (2,728 available).
Q2432. How to make AJAX call and in which component lifecycle methods should I make an AJAX call?
You can use AJAX libraries such as Axios, jQuery AJAX, and the browser built-in `fetch`. You should fetch data in the `componentDidMount()` lifecycle method. This is so y...
Q2433. Is Node.js completely single threaded?
Node is a single thread, but some of the functions included in the Node.js standard library(e.g, fs module functions) are not single threaded. i.e, Their logic runs outsi...
Q2434. What are render props?
**Render Props** is a technique for sharing code/logic between components using a prop whose value is a function that returns a React element. Instead of duplicating stat...
Q2435. What are the common use cases of observables?
An **Observable** (popularized by RxJS and reactive programming) represents a lazy, push-based stream of multiple values emitted over time. Observables excel at handling ...
Q2436. How to dispatch an action on load?
You can dispatch an action in `componentDidMount()` method and in `render()` method you can verify the data. ```javascript class App extends Component { componentDidMount...
Q2437. What is RxJS?
RxJS (Reactive Extensions for JavaScript) is a library for implementing reactive programming using observables that makes it easier to compose asynchronous or callback-ba...
Q2438. How to use `connect()` from React Redux?
You need to follow two steps to use your store in your container: 1. **Use `mapStateToProps()`:** It maps the state variables from your store to the props that you specif...
Q2439. What is the difference between Function constructor and function declaration?
The functions which are created with `Function constructor` do not create closures to their creation contexts but they are always created in the global scope. i.e, the fu...
Q2440. Whats the purpose of `at` symbol in the Redux connect decorator?
The **@** symbol is in fact a JavaScript expression used to signify decorators. _Decorators_ make it possible to annotate and modify classes and properties at design time...