The withDefaults function loses arguments when assigning a function default value

[hcg1023]

Version

3.2.26

Reproduction link

sfc.vuejs.org/

Steps to reproduce

const props = withDefaults(defineProps<{
  fn?: (name: string) => void
}>(), {
  fn(name: string) {
    return name.toUpperCase()
  }
})
console.log(props.fn)

What is expected?

Returns the correct default value

What is actually happening?

Function defaults lose arguments

[jacekkarczmarczyk]

Arrow function seems to work

[hcg1023]

Arrow function seems to work
Can you give me a simple example? It doesn't seem to work if I try
sfc.vuejs.org/

[jacekkarczmarczyk]

example

[hcg1023]

example

Thank you, but why doesn't my way of writing it work? I think it's still a bug

[LinusBorg]

When using a method like you do, you would have to explicitly type this: undefined as the first argument of the method.

[hcg1023]

When using a method like you do, you would have to explicitly type this: undefined as the first argument of the method.

I specified this: undefined as you said, but it still does not work properly. I have tried three ways of writing, maybe you need to teach me

sfc.vuejs.org

[LinusBorg]

The mentioned fact that you need to use an arrow function or annotate this properly is documented here:

https://v3.vuejs.org/guide/typescript-support.html#annotating-props

But indeed, a method with this: undefined doesn't work work on withDefaults(). But it does with arrow functions. Not sure if this is a necessary consequence of the TS limitation mentioned in the docs or we can fix it.

[hcg1023]

I created a PR for this problem #5615