esbuild is the current darling leading the pack, but there are also various other projects in the space (swc[0] is written in Rust, fjb[1] is written in C, bun[

esbuild is the current darling leading the pack, but there are also various other projects in the space (swc[0] is written in Rust, fjb[1] is written in C, bun[2] is written in zig, leveraging JavascriptCore's engine). The most significant performance-oriented effort in this space still leveraging JS that I know of is kataw[3], and while that's quite fast compared to babel, it's still within an order of magnitude from babel. Kataw itself is a CST-based implementation that was created to outperform seafox (a AST-based parser by the same developer), which itself is an iteration over several other perf-oriented parser projects. Babel gained popularity due to the crazy amount of churn in grammar over the past few years, but more and more I think the dust is settling, and flexibility is no longer the name of the game, making an AST-based implementation less appealing. The Rome team must be feeling the heat if the data structure design choices are being informed by performance. I highly doubt someone will be able to compete in performance using a JS implementation in today's landscape. [0] https://github.com/swc-project/swc https://github.com/swc-project/swc [1] https://github.com/sebbekarlsson/fjb https://github.com/sebbekarlsson/fjb [2] https://bun.sh/ https://bun.sh/ [3] https://github.com/kataw/kataw https://github.com/kataw/kataw