useElementVisibility

类别

Elements

导出体积

796 B

上次更改

last week

跟踪元素在视口内的可见性。

示例

源码 playground (beta)

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
('target')
const targetIsVisible
 = useElementVisibility
(target
)

const target2
 = useTemplateRef
('target2')
const targetVisibilityController
 = useElementVisibility
(target2
, { controls
: true })
</script>

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

  <div
 ref
="target2
">
    <h1
>Hi there</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',
})

threshold

如果您想控制更新值所需的可见性百分比，可以使用 threshold 选项（请参见 MDN IntersectionObserver/threshold）。

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

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

function onElementVisibility
(state
) {
  isVisible
.value
 = state

}

const target2
 = useTemplateRef
('target2')
const isVisible2
 = shallowRef
(false)

function onElementVisibilityWithControls
(state
) {
  isVisible2
.value
 = state
.isVisible.value
  if (state
.isVisible.value) {
    state
.stop()
  }
}
</script>

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

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

  <!-- 带控制 -->
  <div
 ref
="target2
">
    <div
 v-element-visibili
ty="[
onElementVisibilityWithControls
, { 
controls
: true }]
">
      {{ isVisible2
 ? 'inside' : 'outside' }}
    </div
>
  </div
>
</template>

类型声明

显示类型声明

export interface UseElementVisibilityOptions
<Controls
 extends boolean = false>
  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
  /**
   * Expose more controls
   *
   * @default false
   */
  controls
?: Controls

}
export type UseElementVisibilityReturn
<Controls
 extends boolean = false> =
  Controls
 extends true
    ? UseElementVisibilityReturnWithControls
    : ShallowRef
<boolean>
export interface UseElementVisibilityReturnWithControls extends UseIntersectionObserverReturn {
  isVisible
: ShallowRef
<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
<false>,
): UseElementVisibilityReturn
<false>
export declare function useElementVisibility
(
  element
: MaybeComputedElementRef
,
  options
?: UseElementVisibilityOptions
<true>,
): UseElementVisibilityReturn
<true>