v-if type guard does not effect events

[markbrockhoff]

Hi,

I noticed that the "type guard" functionality given by v-if effects props and the template but not events.

Example:

In this example I have a ref of an object called selectedDepartment the whole object can be undefined. To eliminate this case I use a v-if as a type guard to check that it is defined before using it inside the template.
This works like a normal if in typescript for the prop and template, but not the event.
I'd expect Volar to reduce the type of selectedDepartment to not be undefined like in the prop:

[xiaoxiangmoe]

This is because callback function may be called at any time.
For example:

setTimeout(()=>{
   emit('click')
}, 100*1000);

This will emit click after 100s, but component may be destroyed at 50s.
So the type narrow in callback function is unsound.

---

But if you really want to use it, for the sake of completeness, see #1750 (comment)

[markbrockhoff]

Ok, I see. Thanks for the quick answer.