stack/v1/packages/mosaic/framework/skills/vueuse-functions/references/useElementVisibility.md

category

category
Elements

useElementVisibility

Tracks the visibility of an element within the viewport.

Usage

<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).

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).

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

Component Usage

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

Directive Usage

<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

export interface UseElementVisibilityOptions
  extends ConfigurableWindow, Pick<UseIntersectionObserverOptions, 'threshold'> {
  /**
   * Initial value.
   *
   * @default false
   */
  initialValue?: boolean;
  /**
   * @see https://developer.mozilla.org/en-US/docs/Web/API/IntersectionObserver/rootMargin
   */
  rootMargin?: MaybeRefOrGetter<string>;
  /**
   * The element that is used as the viewport for checking visibility of the target.
   */
  scrollTarget?: MaybeRefOrGetter<HTMLElement | undefined | null>;
  /**
   * Stop tracking when element visibility changes for the first time
   *
   * @default false
   */
  once?: boolean;
}
/**
 * Tracks the visibility of an element within the viewport.
 *
 * @see https://vueuse.org/useElementVisibility
 */
export declare function useElementVisibility(
  element: MaybeComputedElementRef,
  options?: UseElementVisibilityOptions,
): ShallowRef<boolean, boolean>;
export type UseElementVisibilityReturn = ReturnType<typeof useElementVisibility>;