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@tdchien
Last active March 26, 2021 00:26
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Class able to convert a flat array with parent ID's to a nested tree. @link http://blog.tekerson.com/2009/03/03/converting-a-flat-array-with-parent-ids-to-a-nested-tree/
<?php
namespace App\Libraries;
/**
* Class able to convert a flat array with parent ID's to a nested tree
*/
class FlatToTreeConverter
{
/**
* Convert a flat array with parent ID's to a nested tree
*
* @link http://blog.tekerson.com/2009/03/03/converting-a-flat-array-with-parent-ids-to-a-nested-tree/
*
* @param array $array Flat array
* @param string $idKeyName Key name for the element containing the item ID
* @param string $parentIdKey Key name for the element containing the parent item ID
* @param string $childNodesField Key name for the element for placement children
*
* @return array
*/
public static function convert(array $array, $idKeyName = 'id', $parentIdKey = 'parentId', $childNodesField = 'children')
{
$indexed = array();
// first pass - get the array indexed by the primary id
foreach ($array as $row) {
$indexed[$row[$idKeyName]] = $row;
$indexed[$row[$idKeyName]][$childNodesField] = array();
}
// second pass
$root = array();
foreach ($indexed as $id => $row) {
$indexed[$row[$parentIdKey]][$childNodesField][$id] = &$indexed[$id];
if (!$row[$parentIdKey]) {
$root[$id] = &$indexed[$id];
}
}
return $root;
}
}
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