ajax_object is not defined when ajax calls the function

As Codex says,

IMPORTANT! wp_localize_script() MUST be called after the script has
been registered using wp_register_script() or wp_enqueue_script().

add_action( 'init', 'my_script_enqueuer' );
function my_script_enqueuer() {
  wp_enqueue_script( 'jquery' );
  # before enqueue,if not register then register  
  wp_enqueue_script( 'add-order-front' );
  wp_localize_script( 'add-order-front', 'ajax_object', array( 'ajax_url' => admin_url( 'admin-ajax.php' ) ) );
}