Getting Started With Webpack: Everything You Need To Know

December 2

Over the years, there have been considerable improvements in technology. The Internet went from being a luxurious service to a basic necessity. The improvements in mobile devices, internet accessibility, and affordability have accompanied this transformation. In addition to these one another significant change that improved user experience is the implementation of modular programming support through node.js. In the early days of JavaScript, although there was support for modularity, no native browsers provided support. These problems were solved by module bundlers like Webpack, Parcel, rollup, and Google's closure compiler. These new compilers enabled end-user browsers to download the modular code and execute thereby providing a dynamic user experience.

There have been a lot of changes within the browsers and server-side codes that improved the end-user experience. To fully understand and analyze the changes, it is important to know: What is Webpack?, How Webpack dev server work? and other aspects of module bundlers. Knowing these things will help you better develop your website. 

What is Webpack?

Webpack is a static module bundler designed by Tobias Koppers. It is a highly extensible and configurable tool for JavaScript applications that can be used in both large-scale and small-scale projects. Ever since a wide range of resources have been used for rendering a web page, the server-side functions were limited, and the user-end browser had to take all the workload.

This gave birth to the concept of compiling and optimizing multiple modules and resources into production-ready bundles. Such compiling and optimizations are carried out using module bundlers similar to Webpack. Therefore, Webpack has an integral role in configuring all resources.


As the figure shows, the Webpack bundler looks at the application from the root entry point, compiles all the necessary dependencies by looking through a dependency graph, and then produces an optimized bundle with all the resources and modules. 

To know how Webpack works, here are some of the key terminologies:

  • Chunk: It consists of all the codes that are necessary for execution. All other resources like images, styles and fonts are stored separately. This helps in efficient resource management of all files. 


  • Modules: Modules created using ES6, commonjs, and AMD syntax are supported by Webpack. These modules include the simplified parts of the application that are imported to perform specific functions. 


  • Assets: All the static files and resources that are necessary for the rendering and execution of codes are stored in bundles by Webpack. This can vary from images to video files and other dependencies. 


What is a Webpack dev server? How does it work?


Webpack dev server is a web server that can render web pages, and it is based on express. Webpack dev server eliminates the need for other servers like node. It enables you to see your project locally by providing you with a port number that can be used to see, listen, or test the project.

Unlike other rendering servers that often create a distinct file in a folder, Webpack creates a bundled file within the memory. This information is served to express, which creates a web socket connection to render the output on the browser. Any changes made to the entry file will be directly updated in the memory, and changes will be updated in real-time on the dev server.

By making use of the Webpack dev server, you might loose access to the index.html or bundle.js file. As it cannot be found in any distinct folder, all the relevant resources and codes are saved within the memory to save storage space and to reduce update delays. 

To set up a test project, you can use the following codes:

mkdir Webpack-app
cd Webpack-app
npm init –yes
npm i -D Webpack Webpack-cli babel-loader @babel/core
mkdir src dist
touch Webpack.config.js src/index.js

The ‘mkdir’ command initializes a new directory for the project. cd command changes the directory and navigates you to that specific directory. npm init command initiates the javascript library manager and prepares to load the Webpack library modules for live rendering. 

‘mkdir src dist’ creates two new directories for the rendering. touch Webpack command opens up the editor to make changes within the source file. Any such changes are directly updated on the render without further delay. 

Installing and Setting Up Webpack Dev Server

To get started with the Webpack server, you should locally install several libraries, dependencies, and files on your local machine. To get started, you should install the Webpack dev server, HTML Webpack-plugin, and path. 

To install, you can use the command:

 npm i -D Webpack-dev-server html-Webpack-plugin path

The -D flag will save the packages as your dependencies. 

Once the HTML Webpack plugin is installed, it will generate an HTML5 file for you that consists of all the Webpack bundles with script tags. You can add the following code to the Webpack.config.js file:

// Webpack.config.js
const path = require('path');
module.exports = {
  entry: './src/index.js',
  output: {
    filename: 'bundle.js,'
    path: path.resolve(__dirname, 'dist'),
  devServer: {
    contentBase: './dist',
    port: 8080,
    hot: true,
Now, this additional code block needs to be added to the scripts within the package.json file.
"scripts": {
"Webpack-dev-server": "Webpack-dev-server",
   "dev": "Webpack-dev-server --mode=development",
   "prod": "Webpack --mode=production"

Now you can make use of the npm run dev command to spin up the developer environment and to render the index.html file from the memory. You can access the file by navigating to http://localhost:8080/. Since it automatically spins up the dev server in view mode, you don't need to make use of the -watch flag. 

Since we are making use of the Webpack html plugin, it will create an index.html file and include the bundled file from main.js into the script tags. To visualize and access the files created by the html Webpack plugin, you need to run npm run prod. 

Common Issues With Webpack

Although the Webpack server has made it easier to handle and edit codes while getting real-time updates and renders, you can also encounter a number of issues while using Webpack. Some of the most common issues that you might encounter include:

Module Errors: This often occurs when there are missing modules within the local machine. While trying to execute, some of the dependencies and code lines point to unknown locations or modules that are not available, thereby triggering a set of different module errors. You should check the import statements and ensure that all necessary, relevant modules are installed and updated for the application to run smoothly.

Configuration Issues: Loaders and plugins need to be correctly defined and configured in the Webpack. Reiterating and going through all the lines within webpack.config.js and looking for errors and mistakes can help you solve all such issues without further trouble. 

Version Compatibility: Sometimes, you face issues with version incompatibility between Webpack and the plugins or loaders it uses. Reading the documentation and fixing such incompatibility issues can help you quickly solve all such troubles. It can also occur due to delays in updates; thus, rechecking for updates and ensuring the latest version for all such plugins can help you avoid further issues.

Troubleshooting Web Pack Dev Server

Since bugs and errors are common with any application you might need to troubleshoot them on their own. Here are some troubleshooting tips to find and fix some of the most common errors within web pack dev servers.

Checking the Console log for errors: Almost all errors will have the corresponding error codes present within the error log. Checking the console log soon after each error will help you get an idea regarding the accurate description of the error. Once you have enough information about the error, you will be able to find a fix by looking for similar issues in the developer community. 

Ensure Config Updates: Sometimes the application or webpage might run without any issue but there might be bugs that hinder and limit the user experience. This can primarily occur due to the incompatible configs and delays in updating the plugins, loader and configs to the latest version. Since the dependency check will only look for the resources and not check the actual version, it can cause bugs in the render. 

Clear Cache: Even after updating all the necessary resources and making changes in the code files, you might persistently face previous errors. Therefore, clearing the browser cache and RAM before executing again the code can sometimes clear all the bugs. These types of bugs occur due to the previous render pertaining to computer memory and not properly closing itself. 

EADDRINUSE Error: While trying to execute the project and render the website, you might face:

      throw er; // Unhandled 'error' event
Error: listen EADDRINUSE address already in use :::8080
... etc, and many more lines

This primarily occurs due to the 8080 port being active and occupied by some other program or project. This can easily be solved by closing all other applications, projects, and renders and by re-executing the same source code. 

Unknown property ‘contentBase’ Error: You might also face

[Webpack-cli] Invalid options object error. This indicates webpack dev Server has been initialized using an options object that does not match the API schema specified. The error will be detailed as:

- options has an unknown property 'contentBase'. Etc.…

This occurs due to devpack server configuration and differences between Webpack 3 and Webpack 4. This issue can be addressed by changing the directory property within config files. You can change the content base property to static.

//Webpack 4
    devServer: {
        static: {
            directory: path.join(__dirname, '../../dist/client'),

//Webpack 3
    devServer: {
        contentBase: './dist/client',

Advantages Of Webpack 


Webpack offers a wide range of advantages for developers as well as end users. Some of the key advantages offered by web pack include:

Code Blocks: You can split the code into smaller chunks, thereby improving the initial loading time and memory requirements. This can enable browsers to be robust, quick, and iterative while loading each webpage. Using code blocks and modular codes also improves the readability of code and increases the ease of fixing any bugs. It makes it easier to isolate and troubleshoot the errors within the code. 

Asset Management: Webpack can help you improve asset allocation resource usage and make it easy for you to manage and handle all kinds of resources. You might be using image files, video files, styles, and fonts to improve the user interface; Webpack offers a simple, comprehensive solution for web development.  

Plugin Functionality: Webpack offers support for a wide range of plugins that can be leveraged to improve the functionalities. This will also help you to integrate additional functions and solutions within the application itself seamlessly. 

Optimizations: Webpack ensures the optimization of codes by making use of modules, plugins, configs, and code chunks. All these additional options offered by Webpack ensure that your website and the code are optimized in the best way possible for a better user experience while maximizing efficiency and reducing loading speed. 


Webpack is a simple, elegant, comprehensive tool that has revolutionized website development. It has made it easier for developers to read through the code and make modifications to functions with relative ease. 

It has considerably improved the workflow process, design process, and finalization of the design. Since all the renders are simultaneously updated in real time from within the memory the time loss for compiling and executing again is relatively minimal. 

The enhanced features like hot module replacement that helps you directly address and take care of bugs and issues without having to change the entire code help you improve work efficiency. Like any other application or project, Webpack often has some considerable issues that might arise due to human/ machine errors.

By carefully reading the documentation, understanding the error codes and analyzing the codes, you can fix most of the issues and address a majority of the code issues. Thus, you will be able to unlock the full potential of Webpack and increase your development efficiency and performance of the web application to its fullest.







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