Parcel is a web application bundler that falls into the same category as webpack, but with a different approach. Its main selling point is that it can do many things without any configuration and is also fast.
Key Features
Parcel offers a range of features, including:
- Bundling of assets such as JavaScript, CSS, HTML, and images
- Zero configuration code splitting
- Automatic transforms using Babel, PostCSS, and PostHTML
- Hot module replacement
- Caching and parallel processing for faster builds
All of these features can be used without the need for any manual configuration and are designed to ensure speedy development.
Installation
Parcel can be installed using either Yarn or npm. To install with Yarn, use the following command:
yarn global add parcel-bundler
For npm, use the following command:
npm install -g parcel-bundler
Getting Started with Parcel
To start using Parcel, you can point it to an HTML file or a JavaScript file. For example, to watch for changes in an HTML file:
parcel watch index.html
Alternatively, you can specify a JavaScript file:
parcel watch entry.js
Development Server
Parcel comes with a built-in development server, eliminating the need for additional setup. To start the development server, simply run:
parcel index.html
Creating a Production-ready Bundle
When you’re ready to create a production-ready bundle of your application, use the following command:
parcel build index.html
The production bundle will disable hot module replacement and will not watch for changes. It also triggers the NODE_ENV
variable to production
and uses a minifier to optimize the bundle.
Assets
JavaScript
Parcel supports both ES Modules (import...
) and CommonJS (require...
). It also provides automatic code splitting using dynamic imports. This allows you to load dependencies on-demand, improving performance and reducing initial load times.
CSS
Parcel supports plain CSS, Sass, Less, and Stylus. You can also utilize CSS Modules to organize and modularize your CSS code.
Transforms
Parcel automatically detects and uses any configurations you have for Babel, PostCSS, and PostHTML. This means you can leverage these tools without the need for additional setup.
Hot Module Replacement
Hot module replacement (HMR) is a valuable feature when developing applications. With HMR, changes to CSS or JavaScript will be updated in the browser without requiring a page refresh. This provides a smoother development experience, particularly when testing specific functionality.
Parcel vs Webpack
While webpack allows for extensive customization, it often requires complex configuration and can be overwhelming for smaller projects. Parcel, on the other hand, aims to simplify the development process by relying on conventions rather than explicit configuration. It offers many of the same capabilities as webpack but without the need for manual setup.
Webpack 4 introduced a zero-config mode in response to Parcel’s success, but Parcel remains a popular choice for smaller projects where simplicity and ease of use are prioritized. For larger and more complex projects, webpack provides greater flexibility and control.
Tags: web application bundler, development server, production-ready bundle, assets, JavaScript, CSS, transforms, hot module replacement