vue-element-spy

Plugin for detecting when element reaches top of the viewport. The plugin uses Intersection Observer.

Installation

yarn add vue-element-spy

Import

import Vue from 'vue'
import VueElementSpy from 'vue-element-spy'

Vue.use(VueElementSpy)

Browser

<script src="vue.js"></script>
<script src="/node_modules/vue-element-spy/dist/vue-element-spy.js"></script>

Vue.use(VueElementSpy)

Install options

refreshInterval

It's possible to set refreshInterval option for periodical spies refresh. Use if content changes or reflows without scrolling. Default: 250 Disable: 0

Vue.use(VueElementSpy, {refreshInterval: 500})

Usage

v-vue-element-spy directive

v-vue-element-spy observes whether the target element is at the top of the viewport and calls callback.

Beware that v-vue-element-spy has a side effect - an empty div element is appended before the spied element. The reason is that a target element may be bigger then the viewport that's why expected intersection 100% isn't possible and IntersectionObserver will remain silent.

<div v-vue-element-spy="{callback: myCallback}">
<!-- or shortened syntax -->
<div v-vue-element-spy="myCallback">

v-vue-element-spy options

callback: Function - required

Callback function. Two arguments are passed: boolean whether element is reached top, target element.

watchExit: Boolean

Set watchExit to true if you want to observe bottom of the target and get notified when the whole element leaves viewport. Default: false

offset: Number

Set offset value if you want to move activation point in px. Default: 0

context: String || Boolean

By default all spies are in one global context and if second target reaches viewport then first target becomes inactive. Set context to false if you don't want the target to be affected by other spies. Set context to any String values to define separate context for a target. Default: true

shouldSpy: Boolean

Set shouldSpy if you want to conditionally activate/deactivate the spy. Default: true

<div>
  <h1 v-vue-element-spy="{myCallback, context: 'titles'}">Title 1</h1>
  <h1 v-vue-element-spy="{myCallback, context: 'titles'}">Title 2</h1>
  <h1 v-vue-element-spy="{myCallback, context: 'titles'}">Title 3</h1>
</div>