Method getInlineRelation

/**
 * Helper method to calculate inline to non inline relation (before/after positions).
 * Return associated array, which contain dependency (handle) name as key, and list of inline items for each position.
 * Example: ['handle.name' => ['before' => ['inline1', 'inline2'], 'after' => ['inline3', 'inline4']]]
 *
 * Note: If inline asset have a multiple dependencies, then will be used last one from the list for positioning
 *
 * @param   WebAssetItem[]  $assets  The assets list
 *
 * @return  array
 *
 * @since  4.0.0
 */
public function getInlineRelation(array $assets) : array
{
    $inlineRelation = [];
    // Find an inline assets and their relations to non inline
    foreach ($assets as $k => $asset) {
        if (!$asset->getOption('inline')) {
            continue;
        }
        // Add to list of inline assets
        $inlineAssets[$asset->getName()] = $asset;
        // Check whether position are requested with dependencies
        $position = $asset->getOption('position');
        $position = $position === 'before' || $position === 'after' ? $position : null;
        $deps = $asset->getDependencies();
        if ($position && $deps) {
            // If inline asset have a multiple dependencies, then use last one from the list for positioning
            $handle = end($deps);
            $inlineRelation[$handle][$position][$asset->getName()] = $asset;
        }
    }
    return $inlineRelation;
}