Method checkFileExtension

/**
 * Checks the file extension
 *
 * @param   string  $extension  The extension to be checked
 * @param   string  $component  The optional name for the component storing the parameters
 *
 * @return  boolean  true if it passes the checks else false
 *
 * @since   4.0.0
 */
public static function checkFileExtension($extension, $component = 'com_media', $allowedExecutables = array()) : bool
{
    $params = ComponentHelper::getParams($component);
    // Media file names should never have executable extensions buried in them.
    $executables = array_merge(self::EXECUTABLES, InputFilter::FORBIDDEN_FILE_EXTENSIONS);
    // Remove allowed executables from array
    if (count($allowedExecutables)) {
        $executables = array_diff($executables, $allowedExecutables);
    }
    if (in_array($extension, $executables, true)) {
        return false;
    }
    $allowable = array_map('trim', explode(',', $params->get('restrict_uploads_extensions', 'bmp,gif,jpg,jpeg,png,webp,ico,mp3,m4a,mp4a,ogg,mp4,mp4v,mpeg,mov,odg,odp,ods,odt,pdf,ppt,txt,xcf,xls,csv')));
    $ignored = array_map('trim', explode(',', $params->get('ignore_extensions', '')));
    if ($extension == '' || $extension == false || !\in_array($extension, $allowable, true) && !\in_array($extension, $ignored, true)) {
        return false;
    }
    // We don't check mime at all or it passes the checks
    return true;
}