Yes they can. I can't speak for the offer, but I've used both in some testing/research environments.
It's worth noting that they way Webpack will parse classes with any "standard" build process will corrupt WebComponents custom element constructors. Rollup performs well here.
Of course maybe there's a more enlightened method to work with Webpack and WebComponents, but I don't know it.
So I have included both in one of my project-init scripts to run back-and-forth tests and see which performs better for the feature at hand. It's then pretty easy to remove one as a dependency once decided.
It's worth noting that they way Webpack will parse classes with any "standard" build process will corrupt WebComponents custom element constructors. Rollup performs well here.
Of course maybe there's a more enlightened method to work with Webpack and WebComponents, but I don't know it.
So I have included both in one of my project-init scripts to run back-and-forth tests and see which performs better for the feature at hand. It's then pretty easy to remove one as a dependency once decided.