Bun

Bun is a fast JavaScript and TypeScript runtime that also includes a package manager, test runner and bundler in one binary. You can use it for new projects or to speed up an existing Node.js project.

Bun runs JavaScript and TypeScript files directly, so TypeScript needs no separate compile step before you run it. The bun install command reads your existing package.json and installs dependencies, while bun test runs tests with a Jest-style API. It also bundles code for browsers and servers, so one tool covers much of a typical JavaScript workflow.

• Runs TypeScript and JSX files directly
• Package installs with a lockfile you can read
• Test runner with a Jest-style expect API
• Bundler with a dev server and hot reloading
• Works with existing Node.js projects

JavaScript and TypeScript developers who want fewer tools to set up and maintain. It is also useful for teams that want faster installs in local development and CI.

Bun is free to install on Windows, macOS and Linux. Some Node.js packages depend on Node-specific behaviour, so check compatibility before you move a production app. Read the release notes when you upgrade, since the project moves quickly.