# Generate a Rails app with webpack and no importmap
> Creates a new Rails application configured with webpack, the most comprehensive JavaScript bundler offering extensive plugin ecosystem, code splitting, and advanced optimization features for complex applications.

# Rails applications with webpack bundling

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**How do you create a Rails app with webpack?** Use `rails new myapp --javascript=webpack` to generate a new Rails application with webpack configured as the JavaScript bundler, providing the most comprehensive feature set including code splitting, hot module replacement, and extensive plugin ecosystem.
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The `rails new --javascript=webpack` command creates Rails applications equipped with **the most powerful and flexible JavaScript bundler available**. Webpack offers unparalleled configurability and is suitable for complex applications that require a high degree of customization.

## Why webpack for complex applications

**Code splitting capabilities** enable intelligent bundle optimization through dynamic imports. Applications can load only necessary code initially, then fetch additional modules on-demand, dramatically improving initial page load times.

**Hot Module Replacement (HMR)** provides the most advanced development experience available, updating specific modules without full page reloads while preserving application state.

Webpack supports a wide range of features, including code splitting, hot module replacement, and asset management.

## What the Rails generator configures

The generator adds jsbundling-rails to your Gemfile, creates webpack.config.js with Rails-optimized settings, and configures `./bin/dev` for coordinated Rails and webpack processes. Node.js and Yarn must be installed when using webpack.

## Performance considerations

Webpack's performance can be optimized through various configurations, including code splitting and caching strategies, but its complexity can sometimes lead to longer build times. Webpack takes 41+ seconds to bundle 10 copies of three.js compared to esbuild's sub-second performance.

## When to choose webpack

**Choose webpack** for large-scale applications requiring advanced features like sophisticated code splitting, extensive third-party integrations, or complex asset processing pipelines. Webpack is the go-to choice for large-scale applications that need advanced features and a highly customizable build process.