Introduction to React JS

In this handbook, we’ll walk step-by-step through building the Weather App, a sleek and responsive weather forecast web application built using ReactJS. This app allows users to enter the name of any city and view the current weather, along with a dynamic background, animated weather icons (like clouds and sun), real-time clock, and a stylish footer credit.

Doesn’t matter if you're just starting out with React or looking to apply your knowledge to a real-world project, this module will lay the foundation for understanding core React concepts while also creating something functional and fun.

ReactJS is an open-source JavaScript library for building dynamic user interfaces. It allows developers to create reusable UI components using a syntax called JSX, which looks like HTML but runs in JavaScript.

With features like the virtual DOM and one-way data binding, React efficiently updates and renders components based on changes in data, making it ideal for dynamic and real-time web applications.

Its key features include:

• Component-Based Architecture: UI is split into reusable components (like JavaScript functions taking props and returning UI).
• Virtual DOM: React maintains a virtual DOM and only updates parts of the real DOM that change, improving performance.
• JSX Syntax: React uses JSX, a syntax that lets you write HTML-like code in JavaScript, which is then transformed into DOM elements.
• One-Way Data Flow: Data in React flows from parent to child components, simplifying data handling.

These features make React a powerful choice for building interactive front-end applications.