Introduction

JavaScript frameworks make building full web apps easier, faster, and way more scalable. Instead of manually managing the DOM and API logic, frameworks give structure and reusable components.

1. What Is a JavaScript Framework?

A framework provides tools, patterns, and structure for building complex web apps. You stop writing spaghetti JS and start building maintainable systems.

2. The Big Three

React

• Component-based
• Massive ecosystem
• Used by Facebook, Instagram, Discord

import React from "react";

function App() {
  return <h1>Hello React</h1>;
}
    

Vue.js

• Simpler than React
• Great for beginners
• Used by Alibaba, Xiaomi

<template>
  <h1>Hello Vue</h1>
</template>
    

Angular

• Full enterprise framework
• Strict and structured
• Used by Google, Microsoft

@Component({
  selector: "app-root",
  template: "<h1>Hello Angular</h1>"
})
export class AppComponent {}
    

3. Why Use a Framework?

• Easier component reuse
• Automatic DOM updates
• Better state management
• Larger community + packages
• Cleaner code for large apps

4. JSX, Templates & Data Binding

// React JSX
const title = "Hello";
<h1>{title}</h1>;
    

<h1>{{ message }}</h1>
    

<h1>{{ username }}</h1>
    

5. Project Creation Tools

• React: create-react-app, Vite
• Vue: create-vue, Vite
• Angular: Angular CLI

# React
npx create-react-app myapp

# Vue
npm create vue@latest

# Angular
ng new myapp
    

6. Routing & Navigation

Each framework has its own router:

• React Router
• Vue Router
• Angular Router

7. State Management

• Redux (React)
• Pinia / Vuex (Vue)
• NgRx (Angular)

8. When Not to Use a Framework

• Very small UI
• Static pages
• Landers or simple forms

9. When You Should Use One

• Dashboards
• Heavy UI tools
• Real-time apps
• Large multi-page apps

10. Summary

• React = flexible, biggest ecosystem
• Vue = easiest to learn
• Angular = strict enterprise framework
• Frameworks make big apps manageable