Vue-Lazyload
Vue module for lazyloading images in your applications. Some of goals of this project worth noting include:
- Be lightweight, powerful and easy to use
- Work on any image type
- Add loading class while image is loading
- Supports both of Vue 1.0 and Vue 2.0
Table of Contents
- Demo
- Requirements
- Installation
- Usage
- Constructor Options
- Implementation
- Methods
- Authors && Contributors
- License
Demo
Requirements
- Vue.js
1.xor2.x
Installation
npm
$ npm i vue-lazyload -S CDN
CDN: https://unpkg.com/vue-lazyload/vue-lazyload.js
<script src="https://unpkg.com/vue-lazyload/vue-lazyload.js"></script> <script> Vue.use(VueLazyload) ... </script> Usage
main.js:
import Vue from 'vue' import App from './App.vue' import VueLazyload from 'vue-lazyload' Vue.use(VueLazyload) // or with options Vue.use(VueLazyload, { preLoad: 1.3, error: 'dist/error.png', loading: 'dist/loading.gif', attempt: 1 }) new Vue({ el: 'body', components: { App } })template:
<ul> <li v-for="img in list"> <img v-lazy="img.src" > </li> </ul>use v-lazy-container work with raw HTML
<div v-lazy-container="{ selector: 'img' }"> <img data-src="//domain.com/img1.jpg"> <img data-src="//domain.com/img2.jpg"> <img data-src="//domain.com/img3.jpg"> </div>custom error and loading placeholder image
<div v-lazy-container="{ selector: 'img', error: 'xxx.jpg', loading: 'xxx.jpg' }"> <img data-src="//domain.com/img1.jpg"> <img data-src="//domain.com/img2.jpg"> <img data-src="//domain.com/img3.jpg"> </div><div v-lazy-container="{ selector: 'img' }"> <img data-src="//domain.com/img1.jpg" data-error="xxx.jpg"> <img data-src="//domain.com/img2.jpg" data-loading="xxx.jpg"> <img data-src="//domain.com/img3.jpg"> </div>Constructor Options
| key | description | default | options |
|---|---|---|---|
preLoad | proportion of pre-loading height | 1.3 | Number |
error | src of the image upon load fail | 'data-src' | String |
loading | src of the image while loading | 'data-src' | String |
attempt | attempts count | 3 | Number |
listenEvents | events that you want vue listen for | ['scroll', 'wheel', 'mousewheel', 'resize', 'animationend', 'transitionend', 'touchmove'] | Desired Listen Events |
adapter | dynamically modify the attribute of element | { } | Element Adapter |
filter | the image's listener filter | { } | Image listener filter |
lazyComponent | lazyload component | false | Lazy Component |
dispatchEvent | trigger the dom event | false | Boolean |
throttleWait | throttle wait | 200 | Number |
observer | use IntersectionObserver | false | Boolean |
observerOptions | IntersectionObserver options | { rootMargin: '0px', threshold: 0.1 } | IntersectionObserver |
silent | do not print debug info | true | Boolean |
Desired Listen Events
You can configure which events you want vue-lazyload by passing in an array of listener names.
Vue.use(VueLazyload, { preLoad: 1.3, error: 'dist/error.png', loading: 'dist/loading.gif', attempt: 1, // the default is ['scroll', 'wheel', 'mousewheel', 'resize', 'animationend', 'transitionend'] listenEvents: [ 'scroll' ] })This is useful if you are having trouble with this plugin resetting itself to loading when you have certain animations and transitions taking place
Image listener filter
dynamically modify the src of image
Vue.use(vueLazy, { filter: { progressive (listener, options) { const isCDN = /qiniudn.com/ if (isCDN.test(listener.src)) { listener.el.setAttribute('lazy-progressive', 'true') listener.loading = listener.src + '?imageView2/1/w/10/h/10' } }, webp (listener, options) { if (!options.supportWebp) return const isCDN = /qiniudn.com/ if (isCDN.test(listener.src)) { listener.src += '?imageView2/2/format/webp' } } } })Element Adapter
Vue.use(vueLazy, { adapter: { loaded ({ bindType, el, naturalHeight, naturalWidth, $parent, src, loading, error, Init }) { // do something here // example for call LoadedHandler LoadedHandler(el) }, loading (listender, Init) { console.log('loading') }, error (listender, Init) { console.log('error') } } })IntersectionObserver
use Intersection Observer to to improve performance of a large number of nodes.
Vue.use(vueLazy, { // set observer to true observer: true, // optional observerOptions: { rootMargin: '0px', threshold: 0.1 } })Lazy Component
Vue.use(VueLazyload, { lazyComponent: true });<lazy-component @show="handler"> <img class="mini-cover" :src="img.src" width="100%" height="400"> </lazy-component> <script> { ... methods: { handler (component) { console.log('this component is showing') } } } </script>Implementation
Basic
vue-lazyload will set this img element's src with imgUrl string
<script> export default { data () { return { imgObj: { src: 'http://xx.com/logo.png', error: 'http://xx.com/error.png', loading: 'http://xx.com/loading-spin.svg' }, imgUrl: 'http://xx.com/logo.png' // String } } } </script> <template> <div ref="container"> <img v-lazy="imgUrl"/> <div v-lazy:background-image="imgUrl"></div> <!-- with customer error and loading --> <img v-lazy="imgObj"/> <div v-lazy:background-image="imgObj"></div> <!-- Customer scrollable element --> <img v-lazy.container ="imgUrl"/> <div v-lazy:background-image.container="img"></div> <!-- srcset --> <img v-lazy="'img.400px.jpg'" data-srcset="img.400px.jpg 400w, img.800px.jpg 800w, img.1200px.jpg 1200w"> <img v-lazy="imgUrl" :data-srcset="imgUrl' + '?size=400 400w, ' + imgUrl + ' ?size=800 800w, ' + imgUrl +'/1200.jpg 1200w'" /> </div> </template>CSS state
There are three states while img loading
loading loaded error
<img src="imgUrl" lazy="loading"> <img src="imgUrl" lazy="loaded"> <img src="imgUrl" lazy="error"><style> img[lazy=loading] { /*your style here*/ } img[lazy=error] { /*your style here*/ } img[lazy=loaded] { /*your style here*/ } /* or background-image */ .yourclass[lazy=loading] { /*your style here*/ } .yourclass[lazy=error] { /*your style here*/ } .yourclass[lazy=loaded] { /*your style here*/ } </style>Methods
Event Hook
vm.$Lazyload.$on(event, callback) vm.$Lazyload.$off(event, callback) vm.$Lazyload.$once(event, callback)
$onListen for a custom eventsloading,loaded,error$onceListen for a custom event, but only once. The listener will be removed once it triggers for the first time.$offRemove event listener(s).
vm.$Lazyload.$on
Arguments:
{string} event{Function} callback
Example
vm.$Lazyload.$on('loaded', function ({ bindType, el, naturalHeight, naturalWidth, $parent, src, loading, error }, formCache) { console.log(el, src) })vm.$Lazyload.$once
Arguments:
{string} event{Function} callback
Example
vm.$Lazyload.$once('loaded', function ({ el, src }) { console.log(el, src) })vm.$Lazyload.$off
If only the event is provided, remove all listeners for that event
Arguments:
{string} event{Function} callback
Example
function handler ({ el, src }, formCache) { console.log(el, src) } vm.$Lazyload.$on('loaded', handler) vm.$Lazyload.$off('loaded', handler) vm.$Lazyload.$off('loaded')LazyLoadHandler
vm.$Lazyload.lazyLoadHandler
Manually trigger lazy loading position calculation
Example
this.$Lazyload.lazyLoadHandler() Performance
this.$Lazyload.$on('loaded', function (listener) { console.table(this.$Lazyload.performance()) })
Dynamic switching pictures
<img v-lazy="lazyImg" :key="lazyImg.src">Authors && Contributors
- hilongjw
- imcvampire
- darrynten
- biluochun
- whwnow
- Leopoldthecoder
- michalbcz
- blue0728
- JounQin
- llissery
- mega667
- RobinCK
- GallenHu
