@hzzt/v-lazy-image

    1.4.2 • Public • Published

    v-lazy-image

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    A Vue.js component to lazy load an image automatically when it enters the viewport using the Intersection Observer API.

    Do you know VueDose? It's where you can learn tips about the Vue.js ecosystem in a concise format, perfect for busy devs! 🦄

    Demos

    Usage

    npm install v-lazy-image

    Warning: You'll need to install the w3c Intersection Observer polyfill in case you're targeting a browser which doesn't support it.

    You can register the component globally so it's available in all your apps:

    import Vue from "vue";
    import { VLazyImagePlugin } from "v-lazy-image";
    
    Vue.use(VLazyImagePlugin);

    Or use it locally in any of your components:

    import VLazyImage from "v-lazy-image";
    
    export default {
      components: {
        VLazyImage
      }
    };

    You must pass an src property with the link of the image:

    <template>
      <v-lazy-image src="http://lorempixel.com/400/200/" />
    </template>

    That image will be loaded as soon as the image enters the viewport.

    Progressive Loading

    You can use the src-placeholder property to define an image that is shown until the src image is loaded.

    When the src image is loaded, a v-lazy-image-loaded class is added, so you can use it to perform animations. For example, a blur effect:

    <template>
      <v-lazy-image
        src="https://cdn-images-1.medium.com/max/1600/1*xjGrvQSXvj72W4zD6IWzfg.jpeg"
        src-placeholder="https://cdn-images-1.medium.com/max/80/1*xjGrvQSXvj72W4zD6IWzfg.jpeg"
      />
    </template>
    
    <style scoped>
    .v-lazy-image {
      filter: blur(10px);
      transition: filter 0.7s;
    }
    .v-lazy-image-loaded {
      filter: blur(0);
    }
    </style>

    In case you are using Webpack bundler for images too (just like Vue-cli):

    <v-lazy-image
      src="https://cdn-images-1.medium.com/max/1600/1*xjGrvQSXvj72W4zD6IWzfg.jpeg"
      :src-placeholder="require('../assets/img.jpg')"
    />

    You could listen to the intersect and load events for more complex animations and state handling:

    <template>
      <v-lazy-image
        src="https://cdn-images-1.medium.com/max/1600/1*xjGrvQSXvj72W4zD6IWzfg.jpeg"
        src-placeholder="https://cdn-images-1.medium.com/max/80/1*xjGrvQSXvj72W4zD6IWzfg.jpeg"
        @intersect="..."
        @load="..."
      />
    </template>

    @jmperezperez has written about the progressive loading technique on his blog, in case you want a deeper explanation.

    Responsive Images

    Using the srcset property you can set images for different resolutions:

    <template>
      <v-lazy-image
        srcset="image.jpg 1x, image_2x.jpg 2x"
      />
    </template>

    When using the srcset attribute is recommended to use also src as a fallback for browsers that don't support the srcset and sizes attributes:

    <template>
      <v-lazy-image
        srcset="image-320w.jpg 320w, image-480w.jpg 480w"
        sizes="(max-width: 320px) 280px, 440px"
        src="image-480w.jpg"
      />
    </template>

    The srcset prop is combinable with src-placeholder in order to apply progressive loading.

    Picture

    If you want to wrap the img in a picture tag, use the prop usePicture. You can then use slots to add additional elements above the img element`.

    <v-lazy-image
      srcset="image-320w.jpg 320w, image-480w.jpg 480w"
      alt="Fallback"
      use-picture
    >
      <source srcset="image-320w.jpg 320w, image-480w.jpg 480w" />
    </v-lazy-image>

    Renders as:

    <picture>
      <source srcset="image-320w.jpg 320w, image-480w.jpg 480w" />
      <img srcset="image-320w.jpg 320w, image-480w.jpg 480w" alt="Fallback" />
    </picture>

    Note you can use the picture polyfill.

    API

    Aside from the following API, you can pass any img attribute, such as alt, and they'll be added to the rendered <img> tag.

    Fields marked as (*) are required.

    Props

    Name Type Default Description
    src String (*) - Image src to lazy load when it intersects with the viewport
    src-placeholder String ' ' If defined, it will be shown until the src image is loaded.
    Useful for progressive image loading, see demo
    srcset String - Images to be used for different resolutions
    intersection-options Object () => ({}) The Intersection Observer options object.
    use-picture Boolean false Wrap the img in a picture tag.

    Events

    Name Description
    intersect Triggered when the image intersects the viewport
    load Triggered when the lazy image defined in src is loaded
    error Triggered when the lazy image defined in src fails to load

    Install

    npm i @hzzt/v-lazy-image

    DownloadsWeekly Downloads

    3

    Version

    1.4.2

    License

    MIT

    Unpacked Size

    38.2 kB

    Total Files

    15

    Last publish

    Collaborators

    • qifeng.fan
    • fenghao630