swc is a typescript / javascript compiler. It consumes a javascript or typescript file which uses recently added features like async-await and emits javascript code which can be executed on old browsers. It supports all published typescript versions and all valid ecmascript, including some stage 3 proposals as an input, and supports es3 or higher as an output

It's 20x faster than babel on single thread, and 70x faster on 4 core benchmark

spack is a super-fast javascript bundler with tree shaking