function JsCollectionGrouper::group

Puts multiple items into the same group if they are groupable and if they are for the same browsers. Items of the 'file' type are groupable if their 'preprocess' flag is TRUE. Items of the 'external' type are not groupable.

Also ensures that the process of grouping items does not change their relative order. This requirement may result in multiple groups for the same type and browsers, if needed to accommodate other items in between.

Overrides AssetCollectionGrouperInterface::group

File

core/lib/Drupal/Core/Asset/JsCollectionGrouper.php, line 21

Class

JsCollectionGrouper

Groups JavaScript assets.

Namespace

Code

public function group(array $js_assets) {
    $groups = [];
    // If a group can contain multiple items, we track the information that must
    // be the same for each item in the group, so that when we iterate the next
    // item, we can determine if it can be put into the current group, or if a
    // new group needs to be made for it.
    $current_group_keys = NULL;
    $index = -1;
    foreach ($js_assets as $item) {
        // The browsers for which the JavaScript item needs to be loaded is part
        // of the information that determines when a new group is needed, but the
        // order of keys in the array doesn't matter, and we don't want a new
        // group if all that's different is that order.
        ksort($item['browsers']);
        switch ($item['type']) {
            case 'file':
                // Group file items if their 'preprocess' flag is TRUE.
                // Help ensure maximum reuse of aggregate files by only grouping
                // together items that share the same 'group' value.
                $group_keys = $item['preprocess'] ? [
                    $item['type'],
                    $item['group'],
                    $item['browsers'],
                ] : FALSE;
                break;
            case 'external':
                // Do not group external items.
                $group_keys = FALSE;
                break;
        }
        // If the group keys don't match the most recent group we're working with,
        // then a new group must be made.
        if ($group_keys !== $current_group_keys) {
            $index++;
            // Initialize the new group with the same properties as the first item
            // being placed into it. The item's 'data' and 'weight' properties are
            // unique to the item and should not be carried over to the group.
            $groups[$index] = $item;
            unset($groups[$index]['data'], $groups[$index]['weight']);
            $groups[$index]['items'] = [];
            $current_group_keys = $group_keys ? $group_keys : NULL;
        }
        // Add the item to the current group.
        $groups[$index]['items'][] = $item;
    }
    return $groups;
}