REACT JAVASCRIPT
Introduction
● ReactJS is a declarative, efficient, and flexible JavaScript library for building reusable UI
components.
● It is an open-source, component-based front end library responsible only for the view
layer of the application.
● ReactJS is an open-source JavaScript library created by Facebook's Jordan Walke to
make user interfaces for both web and mobile systems.
● React was first used in 2011 on Facebook's newsfeed.
● In 2012, it was used on Instagram, and in 2013 it was made available to the public.
● React is best for applications that change their data quickly and dynamically.
● ReactJS lets programmers build web apps that can change data without reloading the
page.This makes the user experience much faster.
● The best thing about ReactJS is that it is easy to use, and quick.
● A ReactJS application is made up of multiple components, each component responsible
for outputting a small, reusable piece of HTML code.
● The components are the heart of all React applications.
● These Components can be nested with other components to allow complex applications
to be built of simple building blocks.
● ReactJS uses virtual DOM based mechanism to fill data in HTML DOM.
● The virtual DOM works fast as it only changes individual DOM elements instead of
reloading complete DOM every time.
● ReactJS's primary goal is to make user interfaces (UI) that make apps load faster.
● To create React app, we write React components that correspond to various elements. We
organize these components inside higher level components which define the application
structure.
Why React?
● Easy creation of dynamic applications: React makes it easier to create dynamic web
applications because it requires less coding and offers more functionality, as opposed to
JavaScript, where coding often gets complex very quickly.
, ● Improved performance: React uses Virtual DOM, thereby creating web applications
faster. Virtual DOM compares the components’ previous states and updates only the
items in the Real DOM that were changed, instead of updating all of the components
again, as conventional web applications do.
● Reusable components: Components are the building blocks of any React application, and
a single app usually consists of multiple components. These components have their logic
and controls, and they can be reused throughout the application, which in turn
dramatically reduces the application’s development time.
● Unidirectional data flow: React follows a unidirectional data flow. This means that when
designing a React app, developers often nest child components within parent
components. Since the data flows in a single direction, it becomes easier to debug errors
and know where a problem occurs in an application at the moment in question.
● Small learning curve: React is easy to learn, as it mostly combines basic HTML and
JavaScript concepts with some beneficial additions. Still, as is the case with other tools
and frameworks, you have to spend some time to get a proper understanding of React’s
library.
● It can be used for the development of both web and mobile apps: We already know that
React is used for the development of web applications, but that’s not all it can do. There
is a framework called React Native, derived from React itself, that is hugely popular and
is used for creating beautiful mobile applications. So, in reality, React can be used for
making both web and mobile applications.
● Dedicated tools for easy debugging: Facebook has released a Chrome extension that can
be used to debug React applications. This makes the process of debugging React web
applications faster and easier.
Getting Started with React
Getting started with React involves setting up your development environment and creating a
React application. You can use tools like Vite or Create React App (CRA) to quickly set up a
React project. Here's how to get started with both Vite and CRA:
Setting up with Vite
, ● Vite is a fast build tool that focuses on providing a lightning-fast development
experience.
● To set up a React application with Vite, follow these steps:
a. Install Node.js:
Make sure you have Node.js installed on your system. You can download and install it from the
official Node.js website: https://nodejs.org/
b. Create a new React project:
Open your terminal and run the following commands to create a new React project using Vite:
npm create vite@latest my-react-app -- --template react
Replace my-react-app with the name of your project.
c. Navigate to the project directory:
Once the project is created, navigate to the project directory:
cd my-react-app
d. Install Project Dependencies
npm install
e. Start the development server:
To start the development server, run the following command:
npm run dev
This command will start the development server, and you can access your React application at
http://localhost:5173/.
App Structure Explained
my-react-app/
├── node_modules/
├── public/
│ └── vite.svg
├── src/
│ ├── App.jsx
│ ├── index.css
│ ├── main.jsx
Introduction
● ReactJS is a declarative, efficient, and flexible JavaScript library for building reusable UI
components.
● It is an open-source, component-based front end library responsible only for the view
layer of the application.
● ReactJS is an open-source JavaScript library created by Facebook's Jordan Walke to
make user interfaces for both web and mobile systems.
● React was first used in 2011 on Facebook's newsfeed.
● In 2012, it was used on Instagram, and in 2013 it was made available to the public.
● React is best for applications that change their data quickly and dynamically.
● ReactJS lets programmers build web apps that can change data without reloading the
page.This makes the user experience much faster.
● The best thing about ReactJS is that it is easy to use, and quick.
● A ReactJS application is made up of multiple components, each component responsible
for outputting a small, reusable piece of HTML code.
● The components are the heart of all React applications.
● These Components can be nested with other components to allow complex applications
to be built of simple building blocks.
● ReactJS uses virtual DOM based mechanism to fill data in HTML DOM.
● The virtual DOM works fast as it only changes individual DOM elements instead of
reloading complete DOM every time.
● ReactJS's primary goal is to make user interfaces (UI) that make apps load faster.
● To create React app, we write React components that correspond to various elements. We
organize these components inside higher level components which define the application
structure.
Why React?
● Easy creation of dynamic applications: React makes it easier to create dynamic web
applications because it requires less coding and offers more functionality, as opposed to
JavaScript, where coding often gets complex very quickly.
, ● Improved performance: React uses Virtual DOM, thereby creating web applications
faster. Virtual DOM compares the components’ previous states and updates only the
items in the Real DOM that were changed, instead of updating all of the components
again, as conventional web applications do.
● Reusable components: Components are the building blocks of any React application, and
a single app usually consists of multiple components. These components have their logic
and controls, and they can be reused throughout the application, which in turn
dramatically reduces the application’s development time.
● Unidirectional data flow: React follows a unidirectional data flow. This means that when
designing a React app, developers often nest child components within parent
components. Since the data flows in a single direction, it becomes easier to debug errors
and know where a problem occurs in an application at the moment in question.
● Small learning curve: React is easy to learn, as it mostly combines basic HTML and
JavaScript concepts with some beneficial additions. Still, as is the case with other tools
and frameworks, you have to spend some time to get a proper understanding of React’s
library.
● It can be used for the development of both web and mobile apps: We already know that
React is used for the development of web applications, but that’s not all it can do. There
is a framework called React Native, derived from React itself, that is hugely popular and
is used for creating beautiful mobile applications. So, in reality, React can be used for
making both web and mobile applications.
● Dedicated tools for easy debugging: Facebook has released a Chrome extension that can
be used to debug React applications. This makes the process of debugging React web
applications faster and easier.
Getting Started with React
Getting started with React involves setting up your development environment and creating a
React application. You can use tools like Vite or Create React App (CRA) to quickly set up a
React project. Here's how to get started with both Vite and CRA:
Setting up with Vite
, ● Vite is a fast build tool that focuses on providing a lightning-fast development
experience.
● To set up a React application with Vite, follow these steps:
a. Install Node.js:
Make sure you have Node.js installed on your system. You can download and install it from the
official Node.js website: https://nodejs.org/
b. Create a new React project:
Open your terminal and run the following commands to create a new React project using Vite:
npm create vite@latest my-react-app -- --template react
Replace my-react-app with the name of your project.
c. Navigate to the project directory:
Once the project is created, navigate to the project directory:
cd my-react-app
d. Install Project Dependencies
npm install
e. Start the development server:
To start the development server, run the following command:
npm run dev
This command will start the development server, and you can access your React application at
http://localhost:5173/.
App Structure Explained
my-react-app/
├── node_modules/
├── public/
│ └── vite.svg
├── src/
│ ├── App.jsx
│ ├── index.css
│ ├── main.jsx
