GitHub - hilongjw/vue-lazyload: A Vue.js plugin for lazyload your Image or Component in your application. (original) (raw)

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

For Vue 3

Please use vue-lazyload@3.x, see here

Table of Contents

• Demo
• Requirements
• Installation
• Usage
• Constructor Options
• Implementation
  • Basic
  • Css state
• Methods
  • Event hook
  • LazyLoadHandler
  • Performance
• Authors && Contributors
• License

Demo

Demo

Requirements

• Vue.js 1.x or 2.x

Installation

npm

yarn

CDN

CDN: https://unpkg.com/vue-lazyload/vue-lazyload.js

Usage

main.js:

import Vue from 'vue' import App from './App.vue' import VueLazyload from 'vue-lazyload'

Vue.use(VueLazyload)

// or with options const loadimage = require('./assets/loading.gif') const errorimage = require('./assets/error.gif')

Vue.use(VueLazyload, { preLoad: 1.3, error: errorimage, loading: loadimage, attempt: 1 })

new Vue({ el: 'body', components: { App } })

template:

use v-lazy-container work with raw HTML

custom error and loading placeholder image

Constructor Options

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">

Use in list

Implementation

Basic

vue-lazyload will set this img element's src with imgUrl string

 <!-- 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'" />

CSS state

There are three states while img loading

loading loaded error

Methods

Event Hook

vm.$Lazyload.$on(event, callback) vm.$Lazyload.$off(event, callback) vm.$Lazyload.$once(event, callback)

• $on Listen for a custom events loading, loaded, error
• $once Listen for a custom event, but only once. The listener will be removed once it triggers for the first time.
• $off Remove 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

Authors && Contributors

• hilongjw
• imcvampire
• darrynten
• biluochun
• whwnow
• Leopoldthecoder
• michalbcz
• blue0728
• JounQin
• llissery
• mega667
• RobinCK
• GallenHu

License

The MIT License