Custom renderer showing only the last item from an array into grid magento2

I am trying to show all of the postal codes in my grid from the array in column but it showing only the last one.

Array
(
    [0] => Array
        (
            [from_postalcode] => 123
            [to_postalcode] => 123
            [record_id] => 0
            [initialize] => true
        )

    [1] => Array
        (
            [record_id] => 1
            [from_postalcode] => 1234
            [to_postalcode] => 1234
        )

)

And below is my Code:

class PostalCodeArea extends MagentoUiComponentListingColumnsColumn
{
    /**
     * @param MagentoFrameworkViewElementUiComponentContextInterface $context
     * @param MagentoFrameworkViewElementUiComponentFactory $uiComponentFactory
     * @param array $components = []
     * @param array $data = []
     */
    public function __construct(
        MagentoFrameworkViewElementUiComponentContextInterface $context,
        MagentoFrameworkViewElementUiComponentFactory           $uiComponentFactory,
        array                                                        $components = [],
        array                                                        $data = []
    )
    {
        parent::__construct($context, $uiComponentFactory, $components, $data);
    }

    public function prepareDataSource(array $dataSource)
    {
        if (isset($dataSource['data']['items'])) {
            foreach ($dataSource['data']['items'] as &$item) {
                $countryCodes = [];
                $FromToPostalCode = json_decode($item['from_to_postalcode'],true);
                foreach ($FromToPostalCode as $key){
                    foreach ($key as $array => $code) {
                        $item['postalcode_area'] = $code;
                    }

                }



            }
        }

        return $dataSource;
    }
}

I do not really know what to do and I am confused and tired.

Looking for help.
Thanks.