[Bug Report] VSkeletonLoader rendering default slot unconditionally

[lassesteffen]

Environment

Vuetify Version: 2.2.3
Vue Version: 2.6.11
Browsers: Chrome 79.0.3945.117
OS: Mac OS 10.15.2

Steps to reproduce

1. Create a skeleton loader
2. Reference an attribute of an undefined object
3. See that there is a console error about it

Expected Behavior

V-skeleton-loader works similar to a v-if component and does therefore only render the content in the default slot once the loading flag is false.

Actual Behavior

The undefined object is accessed even when the skeleton loader is still loading. The slot is not rendered conditionally

Reproduction Link

https://codepen.io/ellazlo/pen/GRgGovK

Other comments

Is there any workaround? Is this the intended behaviour? If yes than it's kinda unpractical for data fetching, or am I misunderstanding something here?

[johnleider]

This would happen with any custom component: https://codepen.io/johnjleider/pen/oNgyxWX?editors=1011

If you have any additional questions, please reach out to us in our Discord community.

[KaelWD]

Only if you don't conditionally render the slot: https://github.com/vuetifyjs/vuetify/blob/master/packages/vuetify/src/components/VSkeletonLoader/VSkeletonLoader.ts#L146

[KaelWD]

Vue renders slots when proxying them to this.$slots, so it's still broken unless you use a scoped slot: https://codepen.io/kaelwd/pen/qBEKNYP

[bblanchon]

This v-slot trick should definitely go into the documentation.