# Generate a Rails app with esbuild and no importmap
> Creates a new Rails application configured with esbuild, an extremely fast JavaScript bundler written in Go that provides TypeScript and JSX support with minimal configuration.

# Creating Rails applications with esbuild bundling

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**How do you create a Rails app with esbuild?** Use `rails new myapp --javascript=esbuild` to generate a new Rails application with esbuild configured as the JavaScript bundler, providing extremely fast compilation with built-in TypeScript and JSX support.
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The `rails new --javascript=esbuild` command creates Rails applications optimized for modern JavaScript development through **esbuild's revolutionary performance**. esbuild is 10-100x faster than traditional JavaScript bundlers, making it the recommended choice for most Rails applications requiring JavaScript transpilation.

## Why esbuild excels for Rails development

esbuild is written in Go and compiles to native code, while most other bundlers are written in JavaScript. This fundamental difference means **instant feedback loops** with sub-second compilation times that maintain developer flow.

**Zero-configuration TypeScript and JSX support** eliminates complex setup traditionally required for modern JavaScript features. esbuild handles TypeScript transpilation and JSX transformation out of the box, enabling React development without configuration overhead.

## What the Rails generator configures

The generator automatically adds jsbundling-rails to your Gemfile, configures package.json with build scripts, and sets up `./bin/dev` for concurrent Rails server and esbuild watch mode. Node.js and Yarn must be installed when using esbuild.

## Performance advantages

esbuild uses Go's shared memory between threads and parallel garbage collection, while JavaScript has separate heaps per thread. This architecture enables **parallel processing** that leverages multi-core systems effectively.

Benchmark tests show esbuild bundling 10 copies of three.js in under a second, compared to webpack's 41+ seconds.

## When to choose esbuild

**Choose esbuild** for applications requiring TypeScript, JSX, or npm packages with fast development cycles. It provides the best balance of modern JavaScript capabilities and build speed for most Rails applications.