Q51. What is Hoisting?
Hoisting is JavaScript's default behavior where **variable and function declarations** are moved to the top of their scope before code execution. This means you can acces...
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Q52. How to write comments in React?
The comments in React/JSX are similar to JavaScript Multiline comments but are wrapped in curly braces. **Single-line comments:** ```jsx harmony {/* Single-line comments(...
Q53. What are classes in ES6?
In ES6, JavaScript classes are primarily syntactic sugar over JavaScript’s existing prototype-based inheritance. For example, the prototype based inheritance written in f...
Q54. What is reconciliation?
`Reconciliation` is the process through which React updates the Browser DOM and makes React work faster. React use a `diffing algorithm` so that component updates are pre...
Q55. What are closures?
A closure is the combination of a function bundled(enclosed) together with its lexical environment within which that function was declared. i.e, It is an inner function t...
Q56. Does the lazy function support named exports?
No, currently `React.lazy` function supports default exports only. If you would like to import modules which are named exports, you can create an intermediate module that...
Q57. What are modules?
Modules refer to small units of independent, reusable code and also act as the foundation of many JavaScript design patterns. Most of the JavaScript modules export an obj...
Q58. Why React uses `className` over `class` attribute?
React uses **className** instead of **class** because of a JavaScript naming conflict with the class keyword. 1. `class` is a reserved keyword in JavaScript In JavaScript...
Q59. Why do you need modules?
Before ECMAScript 2015 (ES6) introduced native modules (`import`/`export`), JavaScript ran in a single global scope (`window`), leading to variable name collisions, secur...
Q60. What are fragments?
It's a common pattern or practice in React for a component to return multiple elements. _Fragments_ let you group a list of children without adding extra nodes to the DOM...