This document introduces React JS and provides an overview of its key concepts. It discusses why React is used, its component-based architecture, virtual DOM, and one-way data flow. It also explains the difference between declarative and imperative programming and how React uses a declarative approach. Finally, it provides instructions for setting up a local development environment to start building React applications.

1. Introduction to React js
Aya Benkabbour
@ayaintheclouds

2. Course Expectations
+
small project
this course was made for …

3. Why use React ???
https://www.netflix.com/ma-fr/browse/genre/83

4. Why use React ???
https://www.airbnb.fr/

5. Copy and paste …
⇒ Something must be wrong
🚨

6. This is where React come into play !
Component-Based Architecture
Virtual DOM
React Native
Performance
Compatibility
One-Way Data Flow

7. Declarative vs Imperative
React.js is declarative because it allows you to describe what you
want the UI to look like based on the current data or state, and it
handles the underlying operations to achieve that. Vanilla
JavaScript, on the other hand, is often considered imperative
because it requires you to specify each step explicitly to achieve
the desired outcome. The declarative nature of React can make it
easier to reason about and maintain complex user interfaces.

8. Declarative vs Imperative

9. Let’s get our hands dirty !
Browser
local development
using node js (you should install
it , preferably the long time
support version)
simply type “ react.new “ in the
search bar to get a sandbox
in the command line , type the following commands :
npx create-react-app my_application
cd my_application
npm start
you have two options