A bundler, a transpiler, a runtime (designed to be a drop-in replacement for Node.js), test runner, and a package manager - all in one.
Bun's single-file executables turned out to be perfect for distributing CLI tools. You can compile any JavaScript project into a self-contained binary—runs anywhere, even if the user doesn't have Bun or Node installed. Works with native addons. Fast startup. Easy to distribute.