> The bun "rewrite" really is more of a translation of a software that is mainly dogfooded, created with an at best loose regard for a wider ecosystem.

This seems self-contradictory. If it's just a translation, doesn't that mean it remains fully compatible with that wider ecosystem? All the existing APIs retain identical behavior given the preexisting comprehensive test suite that had to go 100% green after all.

> This seems self-contradictory.

It's not.

Passing an existing test suite just moves the optimistic lower bound to incidental compatibility, it doesn't move it to intentional - "regard" implies you gave it thought.

Plus, it's not just about code: it's also about giving the ecosystem a migration path. Dumping 500k LOC on people and discontinuing development of the zig version effective immediately (there hasn't been a release since and the zig tree is only a reference - the build script is removed afaik) is the opposite of what TypeScript did. If you broke someone's N-API module because of a regression not caught by your suite they're now between a rock and a hard place.

The good news is that there's nobody there to notice. The bun userbase is miniscule* compared to TypeScript's.

* negligible? irrelevant? laughably small? I'm struggling to find an adjective that does the difference justice.