Version

3.2.20

Reproduction link

codesandbox.io

Steps to reproduce

Error one => https://codesandbox.io/s/unruffled-snow-3u1ol?file=/src/components/Slider.vue Working one => https://codesandbox.io/s/cold-brook-8cr41?file=/src/components/Slider.vue

What is expected?

Both should work in the same way

What is actually happening?

The ref in OnMount in script setup is undefined

if you change @vue/compiler-sfc to version "3.2.20" in package.json it works. the codesandbox seems to use an older version.

It also works in the playground

@LinusBorg i removed @vue/compiler-sfc in codesandbox, as it's said there : https://www.npmjs.com/package/@vue/compiler-sfc

Note: as of 3.2.13+, this package is included as a dependency of the main vue package and can be accessed as vue/compiler-sfc. This means you no longer need to explicitly install this package and ensure its version match that of vue's. Just use the main vue/compiler-sfc deep import instead.

it's include in vue now right. It should work so. Edit: i did add @vue/compiler-sfc to try, and it's doesn't work too : https://codesandbox.io/s/unruffled-snow-3u1ol?file=/src/components/Slider.vue

@LinusBorg it's not really kind to close issue straight away, like that. I see in your playground it work, cool. But not in my project and not in codesandbox, event if i add a package who said you don't need to include it anymore .... Make a codesandbox work and then you can close it .

@LinusBorg i finally found the issue if i upgrade to "@vitejs/plugin-vue": "^1.9.3" and "vite": "^2.6.7" it works

And it worked in your codesandbox when I sued the appropriate compiler version in dependencies, that's why I closed it. You had it in dependencies, but with version "3.0.0-0".

I don't know what's up with the current state of the sandbox though.

@LinusBorg i did removed the 3.0.0-0 and it's still doesn't in code sandbox.

It works in a fresh Vue CLI (just tried myself) and a fresh Vite project (as per your own comment). I won't try and debug that codeandbox to get it working again.

Thanks for the help, it work on my side now.