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    content-visibility
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    1.2.2 • Public • Published

    content-visibility Chrome

    Published on webcomponents.org npm 7.0.15 Typescript Lit-Element

    <content-visibility> is a simple web component encapsulates modern CSS properties content-visibility and Web API Intersection Observer API to provide cross-browsers solution to skip rendering (layout & painting) elements until it is needed (appears on the viewport) to boosts page performance.

    CSS content-visibility is only supported on Chrome 85+, Chrome Android 85+ and Opera 71+ but not Firefox, Safari and IE unfortunately, see web.dev. Intersection Observer API supports pretty much all browsers except IE, thus an intersection observer polyfill is included for compatible on IE.

    Basically, all children inside it will only be renderred after it appears on viewport.

    <content-visibility>
      {children will not be rendered when outside the first viewport}
    </content-visibility>

    Compatibility

    Chrome Safari Edge IE Firefox Opera

    Getting started

    Install

    npm i content-visibility --save

    Use in JSX (React/Preact)

    import 'content-visibility';
    
    const Content = () => {
      return (
        <content-visibility>
          <Section>...</Section>
          <Section>...</Section>
          <Section>...</Section>
        </content-visibility>
      );
    };

    properties

    containIntrinsicSize

    This is will be set as CSS custom variable for contain-intrinsic-size if browsers support it. see

    <content-visibility containIntrinsicSize="600px">
      {children}
    </content-visibility>

    Performance results

    Rendering frames

    Safari comes with Rendering Frames Timeline tool helps to measure rendering performance. Let's have a look the rendering frames without <content-visibility>, total 97 rendering frames happened on the first view. Rendering Frames - no content-visibility

    Only 47 rendering frames happened on the first view after integrated with <content-visibility> Rendering Frames - content-visibility the rest of 50 rendering frames happened when scorlling to the viewport Rendering Frames - content-visibility scroll

    Rendering & Layout time

    Generally speaking, we can plausibly say rendering & layout time improved around 40%, however benchmark results vary depends on sampling size, environments, tools, implementation and etc. Too many factors could impact benchmark results, so this is just a quick sample results to demonstrate the performance differences.

    Chrome 87.0.4280.141

    CSS content-visibility and contain-intrinsic-size

    Before

    Chrome Before

    After

    Rendering and Painting time reduced around 50%.

    Chrome After

    Firefox 84.0.2

    Before

    Firefox Before

    After

    Firefox After

    License

    Copyright (c) 2021 Brian YP Liu

    Install

    npm i content-visibility

    DownloadsWeekly Downloads

    36

    Version

    1.2.2

    License

    MIT

    Unpacked Size

    18.8 kB

    Total Files

    7

    Last publish

    Collaborators

    • ralphbliu