[chucky]

Their about page (https://rolldown.rs/about) describes why they want to do this, but after reading it I'm still unsure why they can't accomplish their goals by adding features to esbuild? Maybe the project goals are too different?

[no_wizard]

esbuild is and has always been governed strongly by Evan Wallace. I can't vouch for whether or not the Evans (both Wallace and You) talked to each other about it, but I'm almost 100% certain Wallaces' vision for the esbuild project is different than what rolldown is ultimately trying to achieve.

In some respects, rolldown is also the next generation of Rollup (potentially) and is a direct answer to rspack[0], which is a webpack compatible rust based toolchain from ByteDance

[0]: https://www.rspack.dev/

[bastawhiz]

One of the interesting things about rollup is how it compiles code. Instead of building each module as a closure, separating the scopes, it compiles everything as one big closure. This is actually faster to parse and run, and allows you to do much better tree shaking and other optimizations.

If you're doing all that, you could probably support rollup plugins as well, which it sounds like they want to do.