arrayflatterator.php

<?php
 
namespace Bitrix\Iblock\Helpers\Arrays;
 
class ArrayFlatterator
{
    private array $processedKeys = [];
 
    public function __construct(array $processedKeys = [])
    {
        $this->processedKeys = $processedKeys;
    }
 
    public function flatten(array $input): array
    {
        if (!empty($this->processedKeys))
        {
            return $this->flattenWithCheckKeys($input);
        }
 
        foreach ($input as $key => $value)
        {
            if (is_array($value))
            {
                $newItems = $this->getFlattenFields($value, $key);
                foreach ($newItems as $newKey => $newValue)
                {
                    $input[$newKey] = $newValue;
                }
            }
        }
 
        return $input;
    }
 
    private function flattenWithCheckKeys(array $input): array
    {
        foreach ($input as $key => $value)
        {
            if (is_array($value) && in_array($key, $this->processedKeys, true))
            {
                $newItems = $this->getFlattenFields($value, $key);
                foreach ($newItems as $newKey => $newValue)
                {
                    $input[$newKey] = $newValue;
                }
            }
        }
 
        return $input;
    }
 
    private function getFlattenFields(array $fields, string $prefix): array
    {
        $result = [];
 
        foreach ($fields as $name => $value)
        {
            $key = "{$prefix}[{$name}]";
            if (is_array($value))
            {
                array_push($result, ...$this->getFlattenFields($value, $key));
            }
            else
            {
                $result[$key] = $value;
            }
        }
 
        return $result;
    }
}