Browser Metro Bundler

browser-metro is a unique, client-side JavaScript and TypeScript bundler designed to run entirely within a web browser, typically leveraging a Web Worker for performance. Inspired by React Native's Metro bundler, it provides features like Hot Module Replacement (HMR), React Refresh support, and integration with Expo Router for file-based routing. It manages modules through a VirtualFS, performs rapid compilation of TypeScript and JSX via Sucrase transforms, and supports on-demand bundling of npm packages through an external ESM server (e.g., `https://esm.reactnative.run`). As of version 1.0.15, it emphasizes rapid development feedback loops in browser-based playgrounds and development environments. Its key differentiator is its completely client-side operation, removing the need for a Node.js build server for many common development tasks, making it ideal for interactive coding environments and sandboxes.