Bun is an all-in-one toolkit for JavaScript and TypeScript apps.
It ships as a single executable called bun.

At its core is the Bun runtime, a fast JavaScript runtime designed
as a drop-in replacement for Node.js. It's written in Zig and
powered by JavaScriptCore under the hood, dramatically reducing
startup times and memory usage.

It supports TS and JSX out of the box.

The bun command-line tool also implements a test runner,
script runner, and Node.js-compatible package manager, all
significantly faster than existing tools and usable in
existing Node.js projects with little to no changes necessary.