Broken build with `tsdx build --format es`

Current Behavior

In an attempt to speed up my builds (and not need the other formats), I attempted to only build for es by changing the build script in package.json to tsdx build --format es but in doing so, it fails with

(node:89396) UnhandledPromiseRejectionWarning: Error: You must supply an options object to rollup

I thought this might be fixed by this commit in 0.5.10 but even on 0.5.11 it still shows the issue (I did a fresh project with npx tsdx create tsdx-test to verify it wasn’t anything in my project specifically).

Expected behavior

To be able to only build a specific format (and possibly any other way so to optimize). My builds jumped from less than 2 minutes for the full pipeline (not just npm run build) to between 7-8 minutes after changing to tsdx (along with migrating to 99% typescript from ~30% prior). I could see having more Typescript code causing it to be a little slower, but not to this magnitude. I was only performing 1 build before, so I’m hoping going back to that will improve my tsdx build times.

Suggested solution(s)

I thought this commit was the fix, but not sure where the issue is now.

Your environment

Software	Version(s)
TSDX	0.5.11
TypeScript	3.1.6
Browser	Chrome
npm	6.8.0
Operating System	Mac

[sw-yx]

haha enjoy your vacation

[techniq]

The root issue appears to be if you exclude cjs from the formats, so tsdx build --format cjs,es works, but not just tsdx build --format es due to inputOptions being null here.

Excluding umd using --format=cjs,es has dropped a minute or so off my builds, which helps.