Eager loading of images and videos not only makes webpage slow and clumsy but also consumes a lot of bandwidth.
If you use twig
templating system for your view layer, here's a small extension that defers loading of resources so they are loaded when required in viewport.
This extension based on awesome malchata/yall.js aka yet another lazy loader
is fully customisable.
Install
composer require adhocore/twig-yall
Usage
First setup twig to register this extension:
// Use your loader of choice
$twig = new Twig\Environment(new Twig\Loader\ArrayLoader);
// Register Yall with defaults
$twig->addExtension(new Ahc\TwigYall\Yall([
// customisation config:
'placeholder' => 'default.png',
]));
Then wrap your twig template in {% lazyload %}...{% endlazyload %}
like so:
{# sometemplate.twig #}
<img src="apple.jpg" /> {# not lazyloaded #}
{% lazyload %}
<img src="ball.jpg" /> {# lazyloaded #}
<img src="cat.jpg" class="no-lazy" /> {# not lazyloaded #}
<img src="cat.jpg" data-src="..." /> {# not lazyloaded #}
<video poster="vid.jpg"> {# lazyloaded #}
<source src="vid1.mp4"> {# lazyloaded #}
<source src="vid2.mp4"> {# lazyloaded #}
</video>
<video class='no-lazy' src="..."></video> {# not lazyloaded #}
<picture><source src="pic.jpg"></picture> {# lazyloaded #}
{% endlazyload %}
<img src="..."> {# not lazyloaded #}
{{ yallify() }} {# place it in footer #}
Finally when twig compiles to html, above will be rendered as:
<img src="apple.jpg" />
<img class="lazy yall" src="default.png" data-src="ball.jpg" />
<img src="cat.jpg" class="no-lazy" />
<img src="cat.jpg" data-src="..." />
<video class="lazy yall" poster="default.png" data-poster="vid.jpg">
<source class="lazy yall" data-src="vid1.mp4">
<source class="lazy yall" data-src="vid2.mp4">
</video>
<video class='no-lazy' src="..."></video>
<picture><source class="lazy yall" data-src="pic.jpg"></picture>
<img src="...">
<script src="https://polyfill.io/v2/polyfill.min.js?features=IntersectionObserver" async></script>
<script src="https://unpkg.com/yall-js@3.1.7/dist/yall.min.js" async></script>
<script type="text/javascript">
document.addEventListener("DOMContentLoaded", function() {
window.setTimeout(function () { yall({"lazyClass":"lazy"}); }, 99);
});
</script>
adhocore/twig-yall
It is a twig extension around malchata/yall.js
for lazy loading img
, picture
, video
, iframe
etc.
(Also supports source
tag and srcset
attribute).
Eager loading of images and videos not only makes webpage slow and clumsy but also consumes a lot of bandwidth.
If you use twig templating system for your view layer, this extension defers loading of resources so they are loaded only when required in viewport.
Installation
composer require adhocore/twig-yall
Usage
First setup twig to register this extension:
// Use your loader of choice
$twig = new Twig\Environment(new Twig\Loader\ArrayLoader)
// Register Yall with defaults
$twig->addExtension(new Ahc\TwigYall\Yall);
// Configuring Yall instance:
$twig->addExtension(new Ahc\TwigYall\Yall(
'polyfillJs' => '<custom url to polyfill>',
'yallJs
…
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