Unable to check whether an event listener was passed once defineEmits is used

[cellador]

Vue version

3.5.13

Link to minimal reproduction

https://play.vuejs.org/#eNqtUk1PAjEQ/StNY7KakN0Y9IIrUQkHPahREw/WmHUZoLDbNu0USTb73227gAgrJ2/tvDfz3nxU9FqpeGGB9mhqcs0VEgNoVZ8JXiqpkQxkqV45ToclRzLWsiRRnGwHfXp0sceXFltTVvF1Vpo0sk7QfRBKVWQI7kdI+kv6Ki94Pr9klNGkgT81Wb12NXe4abJVl3YomlyKMZ/EMyOF67zyRRjNXRVegH5QyKUwjPZIQDyWFYX8ugsx1BY663g+hXzeEp+ZpY8x+qjBgF4AoxsMMz0BbODh8z0s3XsDlnJkC8c+AD6BkYX1HhvajRUjZ3uLF9zehn1wMXkxwyWCMOumvFHPrAOfUbcJP8C/Wv+x243PQh4TtZvi7g20nNAIxlyAJ5jjtygsJXo/Obx0ozLRryoSSTEICYQLcpQhalPXLtHD+yttua4WP/+v+7EA7QfrxLrxeXzapfU3ZfYh+w==

Steps to reproduce

Check the resulting html

What is expected?

According to the documentation, $attrs collects fallthrough attributes. Therefore it is expected that after using defineEmits(['click']), onClick is no longer present in $attrs. This however means that besides going after the vnode, there is no API to know which listener was passed to a component once defineEmits is used.

What is actually happening?

The component which uses defineEmits(['click']) in its setup is no longer able to check whether the @click="..." attribute was passed.

System Info

No response

Any additional comments?

This makes it impossible to define a component which delivers a default click handler if no click handler is passed from the outside.

[edison1105]

a workaround:

const vnode = getCurrentInstance().vnode
const hasClickListener = vnode ? !!vnode.props.onClick : false

see playground

---

I think you should define an onClick prop like this:

const props = defineProps({
  onClick: {
    type: Function,
    default: () => {
      // default click processing logic
    }
  }
})

If an onClick is passed from the outside, use the passed handler; if not, use the default handler.