Doesn't re-use bundle for caching

[tivac]

It looks like rollup supports setting the cache property on the options to a previously-generated bundle to speed up builds in Bundle.js#L24-L28, which is awesome.

Unfortunately rollup-watch doesn't seem to use this feature to speed up watched builds. Any particular reason? Could it? I'd happily send a PR if it would help! I just switched from browserify + rollupify over to rollup-watch and the lack of incremental builds is pretty brutal.

[Rich-Harris]

Huh – I could have sworn...

That PR would be great, thanks! Note that even with incremental rebuilds, there's a bit of work we still need to do before it's as fast as it can be: rollup/rollup#723

[tivac]

Cool, working on it atm.

[Rich-Harris]

Thanks! Released 2.5.0