Clarification - in the past when I've written high performance data tools in JS, it was almost entirely to support the use case of needing it to run in a browser. Otherwise, there are indeed more suitable environments available.

To your question, I was about to point out Firefox[1], but realized you clarified 'mainstream'[2]...

[1] https://briangrinstead.com/blog/firefox-webcomponents

[2] https://gs.statcounter.com/browser-market-share