jQuery( function( $ ) {
    var bulk_action_1       = $( '#bulk-action-selector-top' ),
    bulk_action_2           = $( '#bulk-action-selector-bottom' ),
    set_pre_order_status    = ywpo_bk_data.set_pre_order_status,
    remove_pre_order_status = ywpo_bk_data.remove_pre_order_status;

    //  Add action on bulk action dropdown to let the user set a custom action for barcode generation.
    bulk_action_1.add( bulk_action_2 ).append( set_pre_order_status, remove_pre_order_status );
} );