Sucrase is an alternative to Babel that allows super-fast development builds. Instead of compiling a large range of JS features down to ES5, Sucrase assumes that you're targeting a modern JS runtime (e.g. Node.js 8 or latest Chrome) and focuses on compiling non-standard language extensions: JSX, TypeScript, and Flow.
Sucrase is an open source tool with 1.7K Github Stars and 33 Github Forks. Here’s a link to Sucrase's open source repository on Github