Filter list by reference intersection

1_Usage.fusion

videos = Neos.Fusion:Loop {
  items = Vendor.Site:VideoNodesByTag {
    tags = 
  }
  renderer = afx`<div>{item.title}</div>`
}

2_VideoNodesByTag.fusion

prototype(Vendor.Site:VideoNodesByTag) < prototype(Neos.Fusion:Component) {
		
	# the tags to search for
	tags = null 
	
	# the video list, by default all videos in the site
	allVideos = ${q(site).find('[instanceof Vendor.Site:Videos]').get()}
	
	renderer = Neos.Fusion:Reduce {
		items = ${props.allVideos}
		carryName = 'carry'
		itemName = 'item'

                # by default the result list is empty array  
		initialValue = ${[]}

                #
		# if no intersection between the tags the carry is returned directly otherwise the item is pushed to the result 
		# this is based on the behavior of php that considers and empty array [] falsy and thus will
                # use the second part of the ternary if no intersection is found
                #
		itemReducer = ${(CustomArray.intersect(props.tags, item.tags)) ? Array.push(carry, item) : carry}
	}
}

3_CustomArrayHelper.php

<?php 
namespace Vendor\Site\Eel

use Neos\Eel\ProtectedContextAwareInterface;

class CustomArrayHelper implements ProtectedContextAwareInterface
{
        /**
         * @param iterable $array Array of elements to test
         * @param iterable $array Array of elements to test
         * @return array the elements that are present in both array
         */
	public function itersect(iterable $a, iterable $b): array
	{
		if ($a instanceof \Traversable) {
            $a = iterator_to_array($array);
        }
        if ($b instanceof \Traversable) {
            $b = iterator_to_array($array);
        }
        
        return array_intersect($a, $b);
	}

        /**
         * All methods are considered safe
         *
         * @param string $methodName
         * @return bool
         */
    public function allowsCallOfMethod($methodName): bool
    {
        return true;
    }
}

4_Settings.yaml

Neos:
  Fusion:
    defaultContext:
      CustomArray: 'Vendor\Site\Eel\CustomArrayHelper'