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Chapter 01 - Inception

Que. What is Emmet ?

Emmet is a free plugin for text editors that allows you to type shortcuts that are then expanded into full pieces of code. It is a popular tool among web developers, as it can help them to save time and effort when writing HTML, CSS, and other code. For example in a HTML file:

  1. html:5 or ! gives :
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
</body>
</html>
  1. div>div>p gives :
<div>
    <div>
        <p></p>
    </div>
</div>

Que. Difference between a Library and Framework ?

Feature Library Framework
Purpose Provides functionality for a specific task provides a structure for developing software applications
Control We control the flow of the application The framework controls the flow of the application
Customizaton More customizable Less customizable
Performance More efficient Less efficient

Que. What is CDN ? Why do we use it?

  • A content delivery network (CDN) is a system of distributed servers (network of proxy servers) that deliver web content to users based on their geographical location.
  • CDNs provide a number of benefits for websites, including improved performance, availability, security, and bandwidth costs. If we are looking for ways to improve our website, using a CDN is a great option.

Que. Why is React known as React?

  • React is called React because of its core principle of being "reactive".The name React signifies the framework's ability to efficiently update and render user interfaces in response to changes in application state.
  • Basically, React is called React because it reacts to changes in data. This is a key feature of React, and it's what makes it so powerful for building user interfaces.

Q: What is crossorigin in script tag?

React is used to enable Cross-Origin Resource Sharing (CORS) for a script tag. CORS is a mechanism that allows a web page to access resources from a different origin. By default, browsers block cross-origin requests to protect against cross-site scripting (XSS) attacks.

Syntax

<script crossorigin="anonymous|use-credentials">

Que. What is difference between React and ReactDOM ?

Feature React ReactDOM
Purpose Creates and Manages the state of our application Renders our React components to the DOM
API Provides methods for creating and managing components, state, and events Provides methods for rendering components to the DOM
Use Cases Used in both web and mobile apps Used only in web apps

Que. What is difference between react.development.js and react.production.js files via CDN?

  • The main difference between react.development.js and react.production.js files via CDN is the file size and the level of optimization.
    • react.development.js is the larger file and is optimized for development. It is used for development purpose.
    • react.production.js is the smaller file and is optimized for performance.It is used for Production.

Q: What is async and defer?

Difference async defer
code <script async src = '...'></script> <script defer src = '...'></script>
Loading sequence Does not guarantee the execution sequense of the script Guarantees the execution sequence of scripts in wich they are ordered.
Execution sequence Loads the scripts while HTML is being rendered. When scripts are loaded, then HTML rendering stops and execution of script starts. When execution is completed, HTML rendering resumes. Loads the scripts while HTML is being rendered. Executes the scripts only after the HTML is completely rendered