#1657 breaks `unrefElement(exposedComponent)`

[CarterLi]

Describe the bug

exposed component is a proxy object which only contains exposed properties. You can get values of public properties like$el but testing their existence will fail if users didn't expose them manually.

'$el' in (plain as VueInstance)

Reproduction

https://stackblitz.com/edit/vitejs-vite-amsrj4/

System Info

With minimal reproduction is provided, this section is meaningless

Used Package Manager

npm

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a VueUse issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to https://github.com/vuejs/core instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion.
• The provided reproduction is a minimal reproducible example of the bug.

[CarterLi]

Ref: element-plus/element-plus#8338 (comment)

@DrJume Ideas?

[DrJume]

I'm sorry for causing this trouble! This issue seems to happen only with Vue components which use expose/defineExpose but don't expose a custom $el property.

It's very likely to be caused by a bug in Vue.js:

• in operator not working correctly with component instance exposeProxy vuejs/core#6137

[DrJume]

Thank you for your insight! I submitted a PR in vuejs/core to fix the underlying? issue.

• fix(runtime-core): in operator returning false for built-in instance properties in exposeProxy (fix #6137) vuejs/core#6138