JSX, Babel and Webpack: The Magic Behind ReactJS

Creating an app in React is a true pleasure, especially coming from programming interactive apps in vanilla JavaScript. React utilizes an object oriented design pattern, with a couple of core concepts that are unique: first, there are components. A component in React is a class which represents an element (or set of elements) in the DOM, which have properties (or props) and can also carry state. State in a React component is reserved for properties that may change over time: the text input on a form, for example, or a button which toggles text displayed to the user. Components are typically separated into discrete files, following the convention ComponentName.js.

The second feature which is distinct to React is JSX. JSX — or JavaScript XML — is a syntax extension to standard JavaScript which allows us to incorporate XML-like syntax into our code. For example, with JSX we are allowed to write the following:

const greeting = <h1>Hello, World!</h1>

This is where things start to get interesting. If you are familiar with HTML, the above should look familiar. With standard JavaScript, however, something like the following would be required to achieve the same result:

const greeting = document.createElement("h1");
greeting.innerText = "Hello, World!";

How exactly does this work and why is it legal? As it turns out, JSX is actually transpiled into standard JavaScript behind the scenes. React uses a preprocessor called Babel to translate our code before it is rendered in the browser. If we head over to the Babel REPL, we can see exactly how our code will be converted:

const greeting = React.createElement("h1", null, "Hello, World!");

This should look familiar! The main difference here is that React uses its own copy of the DOM — the virtual DOM — in order to dynamically handle component loading and unloading (or mounting, in React terminology.)

So, how does React incorporate Babel? This is where Webpack comes in. Webpack is a package bundler for JavaScript that compiles modules into a single source, which is then rendered in the browser. As of ES6, JavaScript introduced the import and export keywords, allowing us to separate out our code into discrete modules and include dependencies. Remember the mention of components being split up into separate files? Webpack first determines the file hierarchy for the project and generates a dependency graph. From the dependency graph it compiles the code to a single source, using Babel to translate and remove the import and export statements, and convert JSX into standard JavaScript.

Let’s create a simple React app to tie all of these concepts together. In your terminal, navigate to your root development directory. Then type:

npx create-react-app my-app

The create-react-app tool does a few things for us, including running npm init and installing Babel and Webpack with some configuration scripts. Let’s move into our new project directory and remove all of the generated source files (as we will create our own from scratch):

cd my-app && rm src/*
touch src/index.js

We will next create a simple app to display and update a greeting as the user types input. Add the following to src/index.js:

import React, { Component, Fragment } from "react";
import ReactDOM from "react-dom";

class App extends Component {
  constructor() {
    super();
    this.state = {
      name: ""
    };
  }

  render() {
    return (
      <Fragment>
        <h1>Hello {this.state.name}</h1>
        <input
          type="text"
          placeholder="Type your name..."
          onChange={e => this.setState({ name: e.target.value })}
        />
      </Fragment>
    );
  }
}

ReactDOM.render(<App />, document.getElementById("root"));

Run yarn start in the terminal, and you should see a header with a text input right below it rendered in the browser. If you copy and paste the code above into the Babel REPL, you can see how the code will be transpiled to vanilla JavaScript. Ok, so now what?

If we poke around in the file structure that create-react-app generated we will notice a file called package.json. This file is responsible for defining project dependencies and scripts such as start and build. Let’s go a level deeper. Type the following into the terminal:

git add .
git commit -m "initial commit"
yarn eject

When prompted, type y to complete the process. What did this do? Well, if we look at our directory structure, we will notice two new folders have been created: config and scripts. By running the eject command, we are removing our dependency on the magic of the create-react-app tool and getting a look under the hood at what’s really happening. Taking a look at package.json now, we can see that there are now many more dependencies listed than before, including Babel and Webpack. Under the config folder that was generated, we also see webpack.config.js and webpackDevServer.config.js. Take a few minutes to peek into these files and try to comprehend what they are doing.

Tying It All Together

React is an amazing framework for quickly creating stunning dynamic web apps, with a lot going on under the hood. JSX is an extension to JavaScript which allows us to write XML-like syntax to define DOM elements, which are translated by Babel into vanilla JS. Webpack is responsible for bundling all of our components together and running a local development server to test our code in the browser. I hope that this article has helped to demystify the magic of React, and bring about a deeper level of understanding.

Go here to view the code presented in this post.

Thanks for reading ❤

If you liked this post, share it with all of your programming buddies!

#reactjs #javascript #web-development

What is GEEK

Buddha Community

JSX, Babel and Webpack: The Magic Behind ReactJS

Tanya Shields

1597755900

ReactJS | Understanding Babel and JSX

ReactJS : ReactJS is an open-source, component-based front-end library which is used only for building the user interfaces. React is flexible and declarative JavaScript Library. Due to slow speed of DOM ( Document Object Model ), React implements a Virtual DOM that is basically an abstraction of DOM. ReactJS also gives us a provision to write the JavaScript and HTML together.

Babel : Babel is a JavaScript compiler that transform the latest JavaScript features, which are not understandable to every browser, into a backward compatible version of JavaScript in current and older browsers or environments.

JSX : JSX is a syntactical extension to JavaScript. It comes with the full power of JavaScript. JSX produces React elements and can embed any JavaScript expression. Ultimately, the JSX is converted to JavaScript using compiler/transformers.

Setting up React and Babel

Get the React and ReactDOM scripts, place it with other scripts and remember to include it every time you use React or ReactDOM.

Now for Babel, create a folder structure say C:\react\work and move to it. We will now install the transpiler for working with Babel. Run the following commands :

npm install babel-cli

npm install babel-preset-react
npm install babel-plugin-transform-react-jsx

#reactjs #babel #html #jsx #javascript #programming

Donna Corriveau

1554869968

JSX, Babel and Webpack: The Magic Behind ReactJS

Creating an app in React is a true pleasure, especially coming from programming interactive apps in vanilla JavaScript. React utilizes an object oriented design pattern, with a couple of core concepts that are unique: first, there are components. A component in React is a class which represents an element (or set of elements) in the DOM, which have properties (or props) and can also carry state. State in a React component is reserved for properties that may change over time: the text input on a form, for example, or a button which toggles text displayed to the user. Components are typically separated into discrete files, following the convention ComponentName.js.

The second feature which is distinct to React is JSX. JSX — or JavaScript XML — is a syntax extension to standard JavaScript which allows us to incorporate XML-like syntax into our code. For example, with JSX we are allowed to write the following:

const greeting = <h1>Hello, World!</h1>

This is where things start to get interesting. If you are familiar with HTML, the above should look familiar. With standard JavaScript, however, something like the following would be required to achieve the same result:

const greeting = document.createElement("h1");
greeting.innerText = "Hello, World!";

How exactly does this work and why is it legal? As it turns out, JSX is actually transpiled into standard JavaScript behind the scenes. React uses a preprocessor called Babel to translate our code before it is rendered in the browser. If we head over to the Babel REPL, we can see exactly how our code will be converted:

const greeting = React.createElement("h1", null, "Hello, World!");

This should look familiar! The main difference here is that React uses its own copy of the DOM — the virtual DOM — in order to dynamically handle component loading and unloading (or mounting, in React terminology.)

So, how does React incorporate Babel? This is where Webpack comes in. Webpack is a package bundler for JavaScript that compiles modules into a single source, which is then rendered in the browser. As of ES6, JavaScript introduced the import and export keywords, allowing us to separate out our code into discrete modules and include dependencies. Remember the mention of components being split up into separate files? Webpack first determines the file hierarchy for the project and generates a dependency graph. From the dependency graph it compiles the code to a single source, using Babel to translate and remove the import and export statements, and convert JSX into standard JavaScript.

Let’s create a simple React app to tie all of these concepts together. In your terminal, navigate to your root development directory. Then type:

npx create-react-app my-app

The create-react-app tool does a few things for us, including running npm init and installing Babel and Webpack with some configuration scripts. Let’s move into our new project directory and remove all of the generated source files (as we will create our own from scratch):

cd my-app && rm src/*
touch src/index.js

We will next create a simple app to display and update a greeting as the user types input. Add the following to src/index.js:

import React, { Component, Fragment } from "react";
import ReactDOM from "react-dom";

class App extends Component {
  constructor() {
    super();
    this.state = {
      name: ""
    };
  }

  render() {
    return (
      <Fragment>
        <h1>Hello {this.state.name}</h1>
        <input
          type="text"
          placeholder="Type your name..."
          onChange={e => this.setState({ name: e.target.value })}
        />
      </Fragment>
    );
  }
}

ReactDOM.render(<App />, document.getElementById("root"));

Run yarn start in the terminal, and you should see a header with a text input right below it rendered in the browser. If you copy and paste the code above into the Babel REPL, you can see how the code will be transpiled to vanilla JavaScript. Ok, so now what?

If we poke around in the file structure that create-react-app generated we will notice a file called package.json. This file is responsible for defining project dependencies and scripts such as start and build. Let’s go a level deeper. Type the following into the terminal:

git add .
git commit -m "initial commit"
yarn eject

When prompted, type y to complete the process. What did this do? Well, if we look at our directory structure, we will notice two new folders have been created: config and scripts. By running the eject command, we are removing our dependency on the magic of the create-react-app tool and getting a look under the hood at what’s really happening. Taking a look at package.json now, we can see that there are now many more dependencies listed than before, including Babel and Webpack. Under the config folder that was generated, we also see webpack.config.js and webpackDevServer.config.js. Take a few minutes to peek into these files and try to comprehend what they are doing.

Tying It All Together

React is an amazing framework for quickly creating stunning dynamic web apps, with a lot going on under the hood. JSX is an extension to JavaScript which allows us to write XML-like syntax to define DOM elements, which are translated by Babel into vanilla JS. Webpack is responsible for bundling all of our components together and running a local development server to test our code in the browser. I hope that this article has helped to demystify the magic of React, and bring about a deeper level of understanding.

Go here to view the code presented in this post.

Thanks for reading ❤

If you liked this post, share it with all of your programming buddies!

#reactjs #javascript #web-development

Byte Cipher

1617110327

ReactJS Development Company USA | ReactJS Web Development Company

ByteCipher is one of the leading React JS app development Companies. We offer innovative, efficient and high performing app solutions. As a ReactJS web development company, ByteCipher is providing services for customized web app development, front end app development services, astonishing react to JS UI/UX development and designing solutions, reactJS app support and maintenance services, etc.

#reactjs development company usa #reactjs web development company #reactjs development company in india #reactjs development company india #reactjs development india

Dexter Goodwin

1650394920

Webpack: A Bundler for Javascript and Friends

webpack

Webpack is a module bundler. Its main purpose is to bundle JavaScript files for usage in a browser, yet it is also capable of transforming, bundling, or packaging just about any resource or asset.

Install

Install with npm:

npm install --save-dev webpack

Install with yarn:

yarn add webpack --dev

Introduction

Webpack is a bundler for modules. The main purpose is to bundle JavaScript files for usage in a browser, yet it is also capable of transforming, bundling, or packaging just about any resource or asset.

TL;DR

Bundles ES Modules, CommonJS, and AMD modules (even combined).
Can create a single bundle or multiple chunks that are asynchronously loaded at runtime (to reduce initial loading time).
Dependencies are resolved during compilation, reducing the runtime size.
Loaders can preprocess files while compiling, e.g. TypeScript to JavaScript, Handlebars strings to compiled functions, images to Base64, etc.
Highly modular plugin system to do whatever else your application requires.

Get Started

Check out webpack's quick Get Started guide and the other guides.

Browser Compatibility

Webpack supports all browsers that are ES5-compliant (IE8 and below are not supported). Webpack also needs Promise for import() and require.ensure(). If you want to support older browsers, you will need to load a polyfill before using these expressions.

Concepts

Plugins

Webpack has a rich plugin interface. Most of the features within webpack itself use this plugin interface. This makes webpack very flexible.

Name	Status	Install Size	Description
[mini-css-extract-plugin][mini-css]	![mini-css-npm]	![mini-css-size]	Extracts CSS into separate files. It creates a CSS file per JS file which contains CSS.
[compression-webpack-plugin][compression]	![compression-npm]	![compression-size]	Prepares compressed versions of assets to serve them with Content-Encoding
[html-webpack-plugin][html-plugin]	![html-plugin-npm]	![html-plugin-size]	Simplifies creation of HTML files (`index.html`) to serve your bundles

Loaders

Webpack enables the use of loaders to preprocess files. This allows you to bundle any static resource way beyond JavaScript. You can easily write your own loaders using Node.js.

Loaders are activated by using loadername! prefixes in require() statements, or are automatically applied via regex from your webpack configuration.

Files

Name	Status	Install Size	Description
[val-loader][val]	![val-npm]	![val-size]	Executes code as module and considers exports as JS code

JSON

Name	Status	Install Size	Description
	![cson-npm]	![cson-size]	Loads and transpiles a CSON file

Transpiling

Status	Install Size	Description
![babel-npm]	![babel-size]	Loads ES2015+ code and transpiles to ES5 using Babel
![type-npm]	![type-size]	Loads TypeScript like JavaScript
![coffee-npm]	![coffee-size]	Loads CoffeeScript like JavaScript

Templating

Status	Install Size	Description
![html-npm]	![html-size]	Exports HTML as string, requires references to static resources
![pug-npm]	![pug-size]	Loads Pug templates and returns a function
![md-npm]	![md-size]	Compiles Markdown to HTML
![posthtml-npm]	![posthtml-size]	Loads and transforms a HTML file using PostHTML
![hbs-npm]	![hbs-size]	Compiles Handlebars to HTML

Styling

Name	Status	Install Size	Description
`<style>`	![style-npm]	![style-size]	Add exports of a module as style to DOM
	![css-npm]	![css-size]	Loads CSS file with resolved imports and returns CSS code
	![less-npm]	![less-size]	Loads and compiles a LESS file
	![sass-npm]	![sass-size]	Loads and compiles a Sass/SCSS file
	![stylus-npm]	![stylus-size]	Loads and compiles a Stylus file
	![postcss-npm]	![postcss-size]	Loads and transforms a CSS/SSS file using PostCSS

Frameworks

Status	Install Size	Description
![vue-npm]	![vue-size]	Loads and compiles Vue Components
![polymer-npm]	![polymer-size]	Process HTML & CSS with preprocessor of choice and `require()` Web Components like first-class modules
![angular-npm]	![angular-size]	Loads and compiles Angular 2 Components
![riot-npm]	![riot-size]	Riot official webpack loader

Performance

Webpack uses async I/O and has multiple caching levels. This makes webpack fast and incredibly fast on incremental compilations.

Module Formats

Webpack supports ES2015+, CommonJS and AMD modules out of the box. It performs clever static analysis on the AST of your code. It even has an evaluation engine to evaluate simple expressions. This allows you to support most existing libraries out of the box.

Code Splitting

Webpack allows you to split your codebase into multiple chunks. Chunks are loaded asynchronously at runtime. This reduces the initial loading time.

Optimizations

Webpack can do many optimizations to reduce the output size of your JavaScript by deduplicating frequently used modules, minifying, and giving you full control of what is loaded initially and what is loaded at runtime through code splitting. It can also make your code chunks cache friendly by using hashes.

Contributing

We want contributing to webpack to be fun, enjoyable, and educational for anyone, and everyone. We have a vibrant ecosystem that spans beyond this single repo. We welcome you to check out any of the repositories in our organization or webpack-contrib organization which houses all of our loaders and plugins.

Contributions go far beyond pull requests and commits. Although we love giving you the opportunity to put your stamp on webpack, we also are thrilled to receive a variety of other contributions including:

Documentation updates, enhancements, designs, or bugfixes
Spelling or grammar fixes
README.md corrections or redesigns
Adding unit, or functional tests
Triaging GitHub issues -- especially determining whether an issue still persists or is reproducible.
Searching #webpack on twitter and helping someone else who needs help
Teaching others how to contribute to one of the many webpack's repos!
Blogging, speaking about, or creating tutorials about one of webpack's many features.
Helping others in our webpack gitter channel.

To get started have a look at our documentation on contributing.

If you are worried or don't know where to start, you can always reach out to Sean Larkin (@TheLarkInn) on Twitter or simply submit an issue and a maintainer can help give you guidance!

We have also started a series on our Medium Publication called The Contributor's Guide to webpack. We welcome you to read it and post any questions or responses if you still need help.

Looking to speak about webpack? We'd love to review your talk abstract/CFP! You can email it to webpack [at] opencollective [dot] com and we can give pointers or tips!!!

Creating your own plugins and loaders

If you create a loader or plugin, we would <3 for you to open source it, and put it on npm. We follow the x-loader, x-webpack-plugin naming convention.

Support

We consider webpack to be a low-level tool used not only individually but also layered beneath other awesome tools. Because of its flexibility, webpack isn't always the easiest entry-level solution, however we do believe it is the most powerful. That said, we're always looking for ways to improve and simplify the tool without compromising functionality. If you have any ideas on ways to accomplish this, we're all ears!

If you're just getting started, take a look at our new docs and concepts page. This has a high level overview that is great for beginners!!

Looking for webpack 1 docs? Please check out the old wiki, but note that this deprecated version is no longer supported.

If you want to discuss something or just need help, here is our Gitter room where there are always individuals looking to help out!

If you are still having difficulty, we would love for you to post a question to StackOverflow with the webpack tag. It is much easier to answer questions that include your webpack.config.js and relevant files! So if you can provide them, we'd be extremely grateful (and more likely to help you find the answer!)

If you are twitter savvy you can tweet #webpack with your question and someone should be able to reach out and help also.

If you have discovered a 🐜 or have a feature suggestion, feel free to create an issue on Github.

Sponsoring

Most of the core team members, webpack contributors and contributors in the ecosystem do this open source work in their free time. If you use webpack for a serious task, and you'd like us to invest more time on it, please donate. This project increases your income/productivity too. It makes development and applications faster and it reduces the required bandwidth.

This is how we use the donations:

Allow the core team to work on webpack
Thank contributors if they invested a large amount of time in contributing
Support projects in the ecosystem that are of great value for users
Support projects that are voted most (work in progress)
Infrastructure cost
Fees for money handling

Author: Webpack
Source Code: https://github.com/webpack/webpack
License: MIT License

#webpack #javascript

Lawrence Lesch

1642275180

Webpack: Packs Commonjs/AMD Modules for The Browser

webpack

Webpack is a module bundler. Its main purpose is to bundle JavaScript files for usage in a browser, yet it is also capable of transforming, bundling, or packaging just about any resource or asset.

Install

Install with npm:

npm install --save-dev webpack

Install with yarn:

yarn add webpack --dev

Introduction

Webpack is a bundler for modules. The main purpose is to bundle JavaScript files for usage in a browser, yet it is also capable of transforming, bundling, or packaging just about any resource or asset.

TL;DR

Bundles ES Modules, CommonJS, and AMD modules (even combined).
Can create a single bundle or multiple chunks that are asynchronously loaded at runtime (to reduce initial loading time).
Dependencies are resolved during compilation, reducing the runtime size.
Loaders can preprocess files while compiling, e.g. TypeScript to JavaScript, Handlebars strings to compiled functions, images to Base64, etc.
Highly modular plugin system to do whatever else your application requires.

Get Started

Check out webpack's quick Get Started guide and the other guides.

Browser Compatibility

Webpack supports all browsers that are ES5-compliant (IE8 and below are not supported). Webpack also needs Promise for import() and require.ensure(). If you want to support older browsers, you will need to load a polyfill before using these expressions.

Concepts

Plugins

Webpack has a rich plugin interface. Most of the features within webpack itself use this plugin interface. This makes webpack very flexible.

Name	Status	Install Size	Description
mini-css-extract-plugin			Extracts CSS into separate files. It creates a CSS file per JS file which contains CSS.
compression-webpack-plugin			Prepares compressed versions of assets to serve them with Content-Encoding
html-webpack-plugin			Simplifies creation of HTML files (`index.html`) to serve your bundles

Loaders

Webpack enables the use of loaders to preprocess files. This allows you to bundle any static resource way beyond JavaScript. You can easily write your own loaders using Node.js.

Loaders are activated by using loadername! prefixes in require() statements, or are automatically applied via regex from your webpack configuration.

Files

Name	Status	Install Size	Description
val-loader			Executes code as module and considers exports as JS code

JSON

Name	Status	Install Size	Description
			Loads and transpiles a CSON file

Transpiling

Templating

Styling

Frameworks

Performance

Webpack uses async I/O and has multiple caching levels. This makes webpack fast and incredibly fast on incremental compilations.

Module Formats

Webpack supports ES2015+, CommonJS and AMD modules out of the box. It performs clever static analysis on the AST of your code. It even has an evaluation engine to evaluate simple expressions. This allows you to support most existing libraries out of the box.

Code Splitting

Webpack allows you to split your codebase into multiple chunks. Chunks are loaded asynchronously at runtime. This reduces the initial loading time.

Optimizations

Webpack can do many optimizations to reduce the output size of your JavaScript by deduplicating frequently used modules, minifying, and giving you full control of what is loaded initially and what is loaded at runtime through code splitting. It can also make your code chunks cache friendly by using hashes.

Contributing

We want contributing to webpack to be fun, enjoyable, and educational for anyone, and everyone. We have a vibrant ecosystem that spans beyond this single repo. We welcome you to check out any of the repositories in our organization or webpack-contrib organization which houses all of our loaders and plugins.

Contributions go far beyond pull requests and commits. Although we love giving you the opportunity to put your stamp on webpack, we also are thrilled to receive a variety of other contributions including:

Documentation updates, enhancements, designs, or bugfixes
Spelling or grammar fixes
README.md corrections or redesigns
Adding unit, or functional tests
Triaging GitHub issues -- especially determining whether an issue still persists or is reproducible.
Searching #webpack on twitter and helping someone else who needs help
Teaching others how to contribute to one of the many webpack's repos!
Blogging, speaking about, or creating tutorials about one of webpack's many features.
Helping others in our webpack gitter channel.

To get started have a look at our documentation on contributing.

If you are worried or don't know where to start, you can always reach out to Sean Larkin (@TheLarkInn) on Twitter or simply submit an issue and a maintainer can help give you guidance!

We have also started a series on our Medium Publication called The Contributor's Guide to webpack. We welcome you to read it and post any questions or responses if you still need help.

Looking to speak about webpack? We'd love to review your talk abstract/CFP! You can email it to webpack [at] opencollective [dot] com and we can give pointers or tips!!!

Creating your own plugins and loaders

If you create a loader or plugin, we would <3 for you to open source it, and put it on npm. We follow the x-loader, x-webpack-plugin naming convention.

Support

We consider webpack to be a low-level tool used not only individually but also layered beneath other awesome tools. Because of its flexibility, webpack isn't always the easiest entry-level solution, however we do believe it is the most powerful. That said, we're always looking for ways to improve and simplify the tool without compromising functionality. If you have any ideas on ways to accomplish this, we're all ears!

If you're just getting started, take a look at our new docs and concepts page. This has a high level overview that is great for beginners!!

Looking for webpack 1 docs? Please check out the old wiki, but note that this deprecated version is no longer supported.

If you want to discuss something or just need help, here is our Gitter room where there are always individuals looking to help out!

If you are still having difficulty, we would love for you to post a question to StackOverflow with the webpack tag. It is much easier to answer questions that include your webpack.config.js and relevant files! So if you can provide them, we'd be extremely grateful (and more likely to help you find the answer!)

If you are twitter savvy you can tweet #webpack with your question and someone should be able to reach out and help also.

If you have discovered a 🐜 or have a feature suggestion, feel free to create an issue on Github.

Author: Webpack
Source Code: https://github.com/webpack/webpack
License: MIT License

#webpack #javascript

JSX, Babel and Webpack: The Magic Behind ReactJS

Tying It All Together

Setting up React and Babel

Tying It All Together

Install

Introduction

Get Started

Browser Compatibility

Concepts

Files

JSON

Transpiling

Templating

Styling

Frameworks

Performance

Module Formats

Contributing

Creating your own plugins and loaders

Support

Sponsoring

Table of Contents

Install

Introduction

Get Started

Browser Compatibility

Concepts

Files

JSON

Transpiling

Templating

Styling

Frameworks

Performance

Module Formats

Contributing

Creating your own plugins and loaders

Support