How to pass ref as prop: [Vue warn]: Invalid prop: type check failed for prop "containerRef". Expected Object, got HTMLDivElement?

Question

I have this template within parent component:

<template>
    <div>
        <div 
            contenteditable
            ref="editorContainer"
        ><editor-content :container-ref="$refs.editorContainer" /></div>
    </div>
</template>

I have this props declaration within "editor-content" component:

props: {
    //...
    containerRef: {
        type: Object,
    }

},

but I get this warning:

[Vue warn]: Invalid prop: type check failed for prop "containerRef". Expected Object, got HTMLDivElement

What should be the type of the ref passing as a prop?

Answer 1

To allow only <div> elements, use type HTMLDivElement .

To allow any element, use type HTMLElement .

To allow anything, set type to null or undefined (that way the linter won't issue a warning).

Answer 2

Here is a full example with TypeScript and Nuxt with SSR.
Added more context via comments.

<script lang="ts">
import { defineComponent, PropType, toRef, watchPostEffect } from '@nuxtjs/composition-api'

export default defineComponent({
  props: {
    element: {
      // When using Nuxt SSR, use this otherwise you get error
      // This allows any HTMLElement type, if want HTMLDivElement just change it
      type: (process.server ? Object : HTMLElement) as PropType<HTMLElement>,
      // let's make it explicit that it does not exist from the begining
      default: undefined,
    },
  },
  setup(props) {
    // Because it can be undefined, let's use `toRef` instead of `toRefs`
    const element = toRef(props, 'element')

    // Optional Effect example
    watchPostEffect((onInvalidate) => {
      // This never happens, on post effect all refs are resolved
      if (!element.value) return

      // Your event listener
      const onScroll = (e: Event) => console.log(e)

      // Add event listener
      element.value.addEventListener('scroll', onScroll, { passive: true })

      // Remove event listener
      onInvalidate(() => element.value.removeEventListener('scroll', onScroll))
    })
  },
})
</script>