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useElementVisibility

.agents/skills/vueuse-functions/references/useElementVisibility.md

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useElementVisibility

Tracks the visibility of an element within the viewport.

Usage

vue
<script setup lang="ts">
import { useElementVisibility } from '@vueuse/core'
import { useTemplateRef } from 'vue'

const target = useTemplateRef('target')
const targetIsVisible = useElementVisibility(target)
</script>

<template>
  <div ref="target">
    <h1>Hello world</h1>
  </div>
</template>

rootMargin

If you wish to trigger your callback sooner before the element is fully visible, you can use the rootMargin option (See MDN IntersectionObserver/rootMargin).

ts
import { useElementVisibility } from '@vueuse/core'
// ---cut---
const targetIsVisible = useElementVisibility(target, {
  rootMargin: '0px 0px 100px 0px',
})

threshold

If you want to control the percentage of the visibility required to update the value, you can use the threshold option (See MDN IntersectionObserver/threshold).

ts
const targetIsVisible = useElementVisibility(target, {
  threshold: 1.0, // 100% visible
})

Component Usage

vue
<template>
  <UseElementVisibility v-slot="{ isVisible }">
    Is Visible: {{ isVisible }}
  </UseElementVisibility>
</template>

Directive Usage

vue
<script setup lang="ts">
import { vElementVisibility } from '@vueuse/components'
import { shallowRef, useTemplateRef } from 'vue'

const target = useTemplateRef('target')
const isVisible = shallowRef(false)

function onElementVisibility(state) {
  isVisible.value = state
}
</script>

<template>
  <div v-element-visibility="onElementVisibility">
    {{ isVisible ? 'inside' : 'outside' }}
  </div>

  <!-- with options -->
  <div ref="target">
    <div v-element-visibility="[onElementVisibility, { scrollTarget: target }]">
      {{ isVisible ? 'inside' : 'outside' }}
    </div>
  </div>
</template>

Type Declarations

ts
export interface UseElementVisibilityOptions
  extends
  ConfigurableWindow,
  Pick<UseIntersectionObserverOptions, 'rootMargin' | 'threshold'> {
  /**
   * Initial value.
   *
   * @default false
   */
  initialValue?: boolean
  /**
   * The element that is used as the viewport for checking visibility of the target.
   */
  scrollTarget?: UseIntersectionObserverOptions['root']
  /**
   * Stop tracking when element visibility changes for the first time
   *
   * @default false
   */
  once?: boolean
}
export type UseElementVisibilityReturn = ShallowRef<boolean>
/**
 * Tracks the visibility of an element within the viewport.
 *
 * @see https://vueuse.org/useElementVisibility
 */
export declare function useElementVisibility(
  element: MaybeComputedElementRef,
  options?: UseElementVisibilityOptions,
): UseElementVisibilityReturn