datatable.directory/app/Tables/JsonExporter.php

<?php


namespace App\Tables;


class JsonExporter extends BaseExporter
{
    /**
     * @return string - mime type for the downloaded file
     */
    protected function getMimeType()
    {
        return 'application/json';
    }

    /**
     * @return string - file extension for the downloaded file
     */
    protected function getFileExtension()
    {
        return 'json';
    }

    /**
     * Write the document to stdout ('php://output')
     */
    protected function writeDocument()
    {
        echo "[\n";

        $first = true;
        foreach ($this->iterateRows() as $row) {
            if ($first) {
                $first = false;
            } else {
                echo ",\n";
            }
            echo json_encode($row, JSON_UNESCAPED_UNICODE|JSON_UNESCAPED_SLASHES);
        }

        echo "\n]\n";
    }
}