What is Vite?

Vite is a modern frontend build tool that combines essential features like bundling imports (similar to Webpack) and compiling TypeScript to JavaScript. It's designed to provide a super-fast development environment and optimized production builds.

• In development, Vite utilizes the browser's native ESModules (ESM) to load only the required files on-demand, skipping the need for a full application bundle.
  → Instead of bundling everything into one file, Vite fetches only the modules specified in the import statements directly.
  → Full bundling is only necessary for production to minimize HTTP requests for better performance.
• In production, Vite uses Rollup, a powerful bundling tool that focuses on optimizing module size and removing unused code.

Key Benefits

• Fast feedback during development with instant Hot Module Replacement (HMR).
• Optimized production builds with lightweight and efficient bundles.

Rollup

Rollup is a bundler optimized for module optimization. Unlike Webpack, Rollup specializes in reducing file size and optimizing the code through Tree Shaking, which removes unused code.

Why Rollup?

• Rollup is focused on lightweight builds and optimization, which makes it ideal for production.
• While Webpack is versatile and suitable for various use cases, Rollup excels in generating smaller, more efficient bundles for better user experience.

ESModules (ESM)

By using ESModules, Vite provides only the necessary files for each page and caches them. When changes occur, only the affected files are fetched again, enabling lightning-fast Hot Module Replacement (HMR) during development.

• ESM (ECMAScript Modules) is a native JavaScript module system supported by modern browsers.
• Vite uses ESM to serve individual modules directly to the browser, eliminating the need to bundle the entire application during development.

Key Features

• Caching: Dependencies are pre-bundled and cached, so only the modified files are reloaded during development.
• On-demand module loading: Only the required files for the current page are fetched, drastically improving speed.

Summary

• In development: Vite serves individual modules without bundling, enabling instant feedback and fast reloads.
• In production: Vite leverages Rollup to create optimized bundles with smaller sizes and better performance.

By combining the best of ESM for development and Rollup for production, Vite provides developers with a fast and modern frontend build tool that improves both the developer and user experience.