1. What is React?
React is a JavaScript library for building fast, interactive, and reusable user interfaces using components.
2.Key Difference Between React and JavaScript
Definition
- Javascript
A programming language used to build logic for web pages (and more)
- React
A library built using JavaScript to create UI components
Purpose
JavaScript
Handles logic, events, API calls, calculations
Works everywhere (frontend + backend with Node.js)
React
Specifically used for building user interfaces (UI)
Focuses on rendering and updating the view
DOM Handling
- JavaScript
Direct DOM manipulation (can get complex)
- React
Uses Virtual DOM (TBD) for efficient updates
JavaScript is a programming language used to build web functionality, while React is a JavaScript library used specifically for building user interfaces in a more efficient and structured way.
3. Why We Use React
React is mainly used to build fast, scalable, and maintainable user interfaces. Here’s the real reasoning behind it
To Build Complex UIs Easily
In Plain Javascript
UI becomes messy as the app grows
Too many DOM manipulations
React solves this with components
Break UI into small reusable parts
Easy to manage large applications
Reusability (Write Once, Use Many Times)
Example
Button component
Card component
Navbar
You create once and reuse everywhere
Saves time
Reduces duplicate code
4. What is a Single Page Application (SPA) in React
A Single Page Application (SPA) in React is a web application that loads a single HTML page and dynamically updates content without reloading the entire page, providing a fast and seamless user experience
How it works in React
In a React app:
Only one main HTML file is loaded (index.html)
React controls everything inside it
When you navigate:
React updates components
No full page reload happens
No full page reload happens
Example (Real Life)
Think about:
Instagram
Gmail
When you click:
- Home → Profile → Messages
Page doesn’t reload
Only content changes
That’s an SPA behavior.
Advantages of SPA
Faster navigation
Better user experience
Less server load after first load
Feels like a mobile app
Disadvantages
Initial load can be slow
SEO can be tricky
Requires JavaScript
5.What is a Multi Page Application (MPA)?
A Multi Page Application (MPA) is a type of web application where every action loads a new HTML page from the server.
In simple words:
- Every time you click something, the whole page reloads.
How it works
User clicks a link (e.g., Home → About)
Browser sends request to server
Server sends a new HTML page
Browser reloads the entire page
Example (Real Life)
Think about:
Amazon (when switching pages)
Old-style websites
Each click = full page refresh
You can actually see the page loading
Advantages of MPA
Better for SEO
Simple architecture
Each page is independent
Disadvantages
Slower navigation
Full page reload every time
Not as smooth as SPA
Easy Analogy
MPA = Opening a new book page every time
SPA = Scrolling inside the same page
6.Libraries vs Frameworks (Key Difference)
Definition
- Library
A collection of pre-written functions that you call when needed
- Framework
A complete structure that calls your code and controls the flow
Control
This is the core concept:
Library → You are in control
Framework → It is in control
Example
Using React
function App() {
return <h1>Hello</h1>;
}
You decide:
when to create components
how to structure your app
You control the flow
Framework Example
Using Angular
Angular decides:
folder structure
architecture
how components interact
Framework controls everything
In Simple Words We Can Say That
A library is a set of tools that developers call when needed, while a framework provides a complete structure and controls the flow of the application using inversion of control.
Inversion Of Control (TBD)
So far you are thinking react is a javascript library and it is not a framework what if i tell you react can be used as a framework by using React Native
React Native(TBD)
Top comments (1)
Nice write-up , Can you say more about Virtual DOM?