VueUse included twice in the bundle (Vue CLI 4.5.15)

[Liwoj]

Repo

Repro:

1. create new project with Vue CLI 4.5.15 (last release version) - select default Vue 3 preset
2. edit package.json and add --report to the build command
3. Build the app - reported size id 88 KB
4. Install @vueuse/core and use it in App.vue (for examle usePreferredColorScheme())
5. Build again - bundle is now 310 KB (+222 KB increase). If you inspect generated report.html it shows both index.mjs and index.cjs from VueUse to be included in the bundle

Any idea what can be the problem ?
I'm also perplexed as it seems whole VueUse/core is included in the bundle although I'm using just single function? Is that Webpack 4 limitation ? Is it possible to get proper tree-shaking with Webpack 4 ?

Thanks

EDIT

• Same applies to @vueuse/shared - again both mjs and cjs files are included in the bundle
• don't know if it is important but I'm using pnpm

Update

Strangely enough, the issue is gone after upgrading from VueUse 7.4.0 to 7.5.1. Bundle size is now down to 150 KB (which still sounds like a lot for using just a single function)

Update 2

I had some spare time so I decided to look more into why including single VueUse function (usePreferredColorScheme) in a fresh Vue CLI app increases bundle size from cca 89 KB to 150 KB

Here are the differences (sizes are "Parsed size" = code after tree-shaking and minification) :

Package	Size diff	Notes
@vueuse/core	+4.06 KB	Just by adding function
@vueuse/shared	+15.3 KB	Report shows index.cjs while @vueuse/core shows index.mjs. Definitely strange.
vue-demi	+9.36 KB (1.06 KB Stat size)	Don' know enough about vue-demi to judge but does not feel right.
vue@3.2.26	(87.49 - 53.91) = +33.58 KB	Little surprising but makes sense as VueUse uses Composition API while clean Vue CLI app not so it is included in the bundle. Tree-shaking of Vue itself definitely works.
SUM	+62.24	Aligns perfectly with sizes reported by Webpack itself

Any comment @antfu ?
Especially the inclusion of Common JS build of @vueuse/shared feels very strange....