useElementVisibility

类别

Elements

导出体积

735 B

上次更改

5 days ago

跟踪元素在视口内的可见性。

示例

源码

右下角的信息

目标元素（向下滚动）

元素外部视口

用法

vue

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

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

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

rootMargin

如果你想在元素完全可见之前更早地触发回调，可以使用 rootMargin 选项（参见 MDN IntersectionObserver/rootMargin）。

const targetIsVisible = useElementVisibility(target, {
  rootMargin: '0px 0px 100px 0px',
})

组件用法

vue

<template>
  <UseElementVisibility v-slot="{ isVisible }">
    是否可见：{{ isVisible }}
  </UseElementVisibility>
</template>

指令用法

vue

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

const target = useTemplateRef<HTMLDivElement>('target')
const isVisible = shallowRef(false)

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

<template>
  <div v-element-visibility="onElementVisibility">
    {{ isVisible ? '在内部' : '在外部' }}
  </div>

  <!-- 使用选项 -->
  <div ref="target">
    <div v-element-visibility="[onElementVisibility, { scrollTarget: target }]">
      {{ isVisible ? '在内部' : '在外部' }}
    </div>
  </div>
</template>

类型声明

typescript

export interface UseElementVisibilityOptions
  extends ConfigurableWindow,
    Pick<UseIntersectionObserverOptions, "threshold"> {
  /**
   * @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
}
/**
 * 跟踪元素在视口中的可见性
 *
 * @see https://vueuse.org/useElementVisibility
 */
export declare function useElementVisibility(
  element: MaybeComputedElementRef,
  options?: UseElementVisibilityOptions,
): ShallowRef<boolean, boolean>