React Styles

Course overview

Uplatz offers comprehensive training on React. This is online video-based training course. You will be awarded Course Completion Certificate at the end of the course.

React is a popular JavaScript library for building user interfaces, particularly single-page applications where updates to the UI need to be fast and responsive. Developed and maintained by Facebook, it allows developers to create reusable UI components, which can then be combined to build complex user interfaces.

React simplifies the process of building complex UIs by breaking them down into smaller, reusable components. It optimizes updates to the user interface using a virtual DOM and encourages a declarative approach to UI development, where developers describe what the UI should look like for a given state, and React takes care of updating the DOM to match.

React Features

1. Components:

   • The core building blocks of React applications.
   • A component is essentially a JavaScript function or class that can accept inputs (called "props") and returns React elements (which describe what should appear on the screen).
   • Components can be stateful (maintain internal data/state) or stateless (purely presentational).

2. JSX (JavaScript XML):

   • A syntax extension for JavaScript that looks similar to HTML.
   • JSX allows developers to write markup directly within JavaScript, making it easier to visualize and build the UI structure.
   • Example of JSX: <div>Hello, world!</div>

3. State:

   • An object that determines how a component renders and behaves.
   • Unlike props, which are passed to the component from the parent, state is managed within the component itself.
   • State changes trigger re-rendering of the component, reflecting updated data in the UI.

4. Props (Properties):

   • Short for properties, props are inputs to components.
   • They are read-only, meaning a component cannot change its own props but can use them to render content.

5. Virtual DOM:

   • React maintains a virtual representation of the DOM (Document Object Model) in memory.
   • When the state of a component changes, React updates the Virtual DOM first.
   • It then compares the updated Virtual DOM with the previous version (a process called "reconciliation") and calculates the most efficient way to update the real DOM to match.
   • This makes updates faster and minimizes direct manipulation of the real DOM.

How React works

1. Component Rendering:

   • When a React component is first rendered, it generates a virtual representation of the DOM (using JSX).
   • This virtual DOM is a lightweight copy of the real DOM elements.

2. State and Prop Changes:

   • When a component’s state or props change, React re-renders the component.
   • It creates an updated virtual DOM to reflect these changes.

3. Reconciliation:

   • React compares the updated virtual DOM with the previous one.
   • It identifies the minimal number of changes needed to update the real DOM, reducing the number of expensive DOM manipulations.

4. Updating the Real DOM:

   • After determining the necessary changes, React updates the real DOM to reflect the new state of the UI.
   • This process is efficient and leads to fast, responsive user interfaces.

5. Lifecycle Methods (for Class Components):

   • In class-based components, React provides lifecycle methods like componentDidMount, componentDidUpdate, and componentWillUnmount.
   • These methods allow developers to hook into different stages of a component’s life (mounting, updating, unmounting).

React Ecosystem

React is often used with other libraries and frameworks to build a complete application:

• React Router: For handling navigation and routing in single-page applications.
• Redux: For managing the global state of an application in a predictable way.
• React Native: For building mobile applications using React.