README.md

vue3-lazyload

A vue3 image lazyload plugin.

Features

• 0 dependencies: No worry about your bundle size
• Type Strong: Written in Typescript
• Support Hook: useLazyload

Installation

$ npm i vue3-img-lazyload
# or
$ yarn add vue3-img-lazyload

Usage

main.js:

import { createApp } from 'vue'
import VueLazyLoad from 'vue3-lazyload'
import App from './App.vue'

const app = createApp(App)
app.use(VueLazyLoad, {
  // options...
})
app.mount('#app')

App.vue:

<template>
  <img v-lazy="your image url" />
</template>

v-lazy use object params

<template>
  <img v-lazy="{ src: 'your image url', loading: 'your loading image url', error: 'your error image url' }">
</template>

Use lifecycle

In main.js

import { createApp } from 'vue'
import VueLazyLoad from 'vue3-lazyload'
import App from './App.vue'

const app = createApp(App)
app.use(VueLazyLoad, {
  loading: '',
  error: '',
  lifecycle: {
    loading: (el) => {
      console.log('loading', el)
    },
    error: (el) => {
      console.log('error', el)
    },
    loaded: (el) => {
      console.log('loaded', el)
    }
  }
})
app.mount('#app')

or

In xxx.vue

Have to be aware of is v-lazy don't use v-lazy="lazyOptions", in this case, vue cannot monitor data changes.

<script>
import { reactive } from 'vue'
export default {
  name: 'App',
  setup() {
    const lazyOptions = reactive({
      src: 'your image url',
      lifecycle: {
        loading: (el) => {
          console.log('image loading', el)
        },
        error: (el) => {
          console.log('image error', el)
        },
        loaded: (el) => {
          console.log('image loaded', el)
        }
      }
    })
    return {
      lazyOptions,
    }
  }
}
</script>

<template>
  <img v-lazy="{src: lazyOptions.src, lifecycle: lazyOptions.lifecycle}" width="100">
</template>

Use Hook

<script lang="ts">
import { ref } from 'vue'
import { useLazyload } from 'vue3-lazyload'
export default {
  name: 'App',
  setup() {
    const src = ref('/example/assets/logo.png')
    const lazyRef = useLazyload(src, {
      lifecycle: {
        loading: () => {
          console.log('loading')
        },
        error: () => {
          console.log('error')
        },
        loaded: () => {
          console.log('loaded')
        }
      }
    })
    return {
      lazyRef
    }
  }
}
</script>

<template>
  <img ref="lazyRef" class="image" width="100">
</template>

Use css state

There are three states while image loading.
You can take advantage of this feature, make different css controls for different states.

• loading
• loaded
• error

<img src="..." lazy="loading">
<img src="..." lazy="loaded">
<img src="..." lazy="error">

<style>
  img[lazy=loading] {
    /*your style here*/
  }
  img[lazy=error] {
    /*your style here*/
  }
  img[lazy=loaded] {
    /*your style here*/
  }
</style>

Delay loading of images

To avoid loading images that are only shortly visible (e. g. fast scrolling through list of images), a delay in milliseconds can be configured. If a delay is set, an image is only loaded if it stays visible for the specified amount of time.

Set delay in object parameter:

<template>
  <img v-lazy="{ src: 'your image url', loading: 'your loading image url', error: 'your error image url', delay: 500 }">
</template>

Options

key	description	default	type
loading	The image used when the image is loaded	-	string
error	The image used when the image failed to load	-	string
observerOptions	IntersectionObserver options	{ rootMargin: '0px', threshold: 0.1 }	IntersectionObserverInit
log	Do print debug info	true	boolean
logLevel	Log level	error	'error' | 'warn' | 'info' | 'debug' | 'log'
lifecycle	Specify state execution function	-	Lifecycle
delay	Time in milliseconds an image has to stay visible before loading starts	0	number

Lifecycle Hooks

key	description
loading	Image loading
loaded	Image loaded
error	Image load error