Uses Passive Event Listeners to Improve Scrolling Performance, should we care?

[the.rampage.rado]

I stumbled upon an easy fix that is recommended a lot online for this notice in Google Page Speed and I would like to ask the members with coding if it works and should we really care about this notice?

https://github.com/zzarcon/default-passive-events

I'm using it by adding this code to Custom code of my thirtybees and when checking with the tool this notice is gone. There are comments online that this file should be loaded before everything else .js and not on the end of the page as we move them with thirtybees. I'm unable to observe any scrolling improvement (or I'm not looking where I should)... Of course one less line in the Google report means the report gathers 1 point overall, not much but in the end if this works it's a five minute job.

 

<script type="text/javascript" src="https://unpkg.com/default-passive-events"></script>

If this works could we implement this tiny .js file locally to avoid using one more connection to external CDN?

[Adik]

Try add code to header.tpl in your theme directory:

<script defer type="text/javascript" src="https://unpkg.com/default-passive-events"></script>
{if isset($js_defer) && !$js_defer && isset($js_files) && isset($js_def)}
    {$js_def}
    {foreach from=$js_files item=js_uri}
            <script defer type="text/javascript" src="{$js_uri|escape:'html':'UTF-8'}"></script>
    {/foreach}
{/if}

 

Edited April 9 by Adik

[the.rampage.rado]

Thanks, this also solves the issue that I had to add it to every shop in the Custom Code section.

[datakick]

I personally don't like this kind of blanket/site wide solution. What if there is some module that actually want to prevent scroll events, for example some module that implements infinite scroll functionality? This could easily break it.

[DRMasterChief]

I am not sure if it is a very good idea to load such code from a 3rd party,  it can become a security thing and also a GDPR problem.

[the.rampage.rado]

Unfortunately I found a UI bug with this approach, some dropdown menus hide right away after showing.