wp localize script is not working in a custom AJAX request

Question

I am trying to use wp_localize_script() to send some php values to a script.

The following are the part of the file inc/show-event.php.

if( $price ) {
    $pricefortwo    = ceil( ( 2 * $price) - ( 0.2 * $price ) );
    $savefortwo     = ( 2 * $price) - $pricefortwo;
    $priceforthree  = ceil( ( 3 * $price) - ( 0.333 * $price ) );
    $saveforthree   = ( 3 * $price) - $priceforthree;
    $priceforretake = ceil( 0.5 * $price );
    $saveforretake  = $price - $priceforretake;

    // Setting the session variables
    $_SESSION['price'] = $price;
    $_SESSION['price_for_two'] = $pricefortwo;
    $_SESSION['price_for_three'] = $priceforthree;
    $_SESSION['price_for_retake'] = $priceforretake;

    $session_array = array(
                'price'         => $_SESSION['price'],
                'price_for_two'     => $_SESSION['price_for_two'],
                'price_for_three'   => $_SESSION['price_for_three'],
                'price_for_retake'  => $_SESSION['price_for_retake']
            );
    wp_localize_script( 'init_show_calendar', 'session_param', $session_array );
}

After this when I try and use the object name session_param in init_show_calendar.js file it throws a js error saying session_param is not defined. but when i use the following code in functions.php.

$session_array = array(
                'price'         => $_SESSION['price'],
                'price_for_two'     => $_SESSION['price_for_two'],
                'price_for_three'   => $_SESSION['price_for_three'],
                'price_for_retake'  => $_SESSION['price_for_retake']
            );
wp_localize_script( 'init_show_calendar', 'session_param', $session_array );

it returns me the variable but it doesn't return the latest values, it returns the value stored in a page refresh.

FYI: The show-event.php is called in a plugin in the following way

add_action('wp_ajax_get_event', array($this, 'render_frontend_modal'));
function render_frontend_modal() {
    require_once AEC_PATH . 'inc/show-event.php';
}

Please let me know if you want any more information.

Answer 1

My need was to set different prices in the session and fetch those in my js script. I am using a jquery session plugin to set and get session, but it wasn't getting session set by php, so I was trying to send variables using wp_localize and set it in the js script.

Taking the clue from @Milo, I passed the values using json_encode and set them to session at the ajax handler end.

This is what i did:--

show-event.php file

 $output = array(
        'price'         => $_SESSION['price'],
        'price_for_two'     => $_SESSION['price_for_two'],
        'price_for_three'   => $_SESSION['price_for_three'],
        'price_for_retake'  => $_SESSION['price_for_retake']
    );
    $this->json_encode( $output );

and in the ajax handler i did:--

// Setting the session value for the prices.
jQuery.session.set('price', data.price);
jQuery.session.set('price_for_two', data.price_for_two);
jQuery.session.set('price_for_three', data.price_for_three);
jQuery.session.set('price_for_retake', data.price_for_retake);

The above sets the session values for the different prices.

I could have also passed the array but I did this which is fine.