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v-viewable ​

The v-viewable directive is for observing the visibility of an element. It uses IntersectionObserver API internally.

The directive bases the visibility on a threshold (default: 1), which is the percentage of the target's visibility at which the callback should be executed. A value of 0 means at least one pixel needs to be visible. A value of 1 means 100% visible.

Import ​

ts
import vViewable from '@leaflink/stash-vue/directives/viewable';

Basic usage ​

The directive requires you pass a function as the value.

vue
<script>
  const isInViewRef = ref(false);
  const entry = ref();

  function onView(isInView, entry) {
    isInViewRef.value = isInView;
    entry.value = entry;
  }
</script>

<template>
  <div class="mb-0 w-12 h-12 bg-red-500" v-viewable="onView"></div>
</template>

Is FULLY visible?: false

Keep scrolling to see the value change...








The function will be called whenever the visiblity of the element changes.

The first argument is a boolean: true when the element is fully in view on the page, false when it's not.

The second argument is the corresponding IntersectionObserverEntry object.

IntersectionObserver options ​

You can optionally provide IntersectionObserver options by providing an object as the directive value with the intersection property. The callback function would instead get passed using the callback property.

template
<div v-viewable="{
  callback: onView,
  intersection: {
    root: ...,
    rootMargin: ...,
    threshold: 0.5,
  },
}">

Once ​

By using the once modifier, you can observe an element only until it's visible. Once visible, the observer will end, and the callback will no longer fire.

jsx
<div v-viewable.once="onView"></div>

Source and credit: https://github.com/Akryum/vue-observe-visibility (no longer maintained)