How to deal with lazy loading of image resources in Vue technology development

How to deal with lazy loading of image resources in Vue technology development

Lazy loading (Lazy Loading) is a common optimization technology that can delay loading of image resources on the page. Image resources, reducing initial loading time and improving user experience. In Vue technology development, we can implement lazy loading of image resources by using third-party libraries or custom instructions. This article will introduce two common lazy loading methods and give specific code examples.

Method 1: Use the third-party library vue-lazyload

vue-lazyload is a Vue-based image lazy loading plug-in, which can help us easily implement lazy loading of image resources. First, we need to install vue-lazyload.

1. Open the terminal in the project root directory and run the following command to install vue-lazyload:

npm install vue-lazyload

2. In the Vue entry file (usually main.js) Introduce vue-lazyload in:

import Vue from 'vue'
import VueLazyload from 'vue-lazyload'

Vue.use(VueLazyload)

3. Use the v-lazy directive in components that need to lazily load images:

<template>
  <div>
    <img src="/static/imghwm/default1.png"  data-src="@/assets/images/image.jpg"  class="lazy"  v-lazy="imageSrc" alt="图片">
  </div>
</template>

<script>
export default {
  data() {
    return {
      imageSrc: require('@/assets/images/image.jpg')
    }
  }
}
</script>

In the above code example, Bind imageSrc to the src attribute of the img tag through the v-lazy instruction. When the img tag enters the visible area, the image resource will be loaded and displayed.

Method 2: Customize instructions to implement lazy loading

In addition to using third-party libraries, we can also customize instructions to implement lazy loading of image resources. The following is a code example that implements lazy loading based on the custom directive of the Intersection Observer API.

// main.js
import Vue from 'vue'

Vue.directive('lazy', {
  inserted: function (el) {
    const observer = new IntersectionObserver(function(entries) {
      const image = entries[0]

      if (image.isIntersecting) {
        loadImage(image.target)
        observer.unobserve(image.target)
      }
    }, { threshold: 0 })

    observer.observe(el)
  }
})

function loadImage(target) {
  const imageSrc = target.getAttribute('data-src')
  if (imageSrc) {
    target.src = imageSrc
  }
}

<template>
  <div>
    <img src="/static/imghwm/default1.png"  data-src="@/assets/images/image.jpg"  class="lazy"  v-lazy="imageSrc" data- alt="图片">
  </div>
</template>

In the above code, we define an insertion instruction inserted and use the Intersection Observer API to monitor the visibility changes of the element. When the image element enters the visible area, the loadImage function is called to load the image resource and display it.

Summary

Lazy loading of image resources is an important optimization strategy in Vue technology development. By delaying the loading of image resources on the page, the initial loading time can be reduced and the user experience can be improved. This article introduces two common implementation methods, one is to use the vue-lazyload third-party library, and the other is to implement custom instructions in combination with the Intersection Observer API. No matter which method is used, lazy loading of image resources can be effectively achieved.

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