Can any one correct the code

I have added a cstm btn in get items from as issue
and it shows a multi dialog box after that when i select the document i need the populate the common fields

frappe.ui.form.on('Sales Invoice', {
    refresh: function(frm) {
        frm.add_custom_button(__('Issue'), function(){
         new frappe.ui.form.MultiSelectDialog({
                doctype: "Issue",
                target: frm,
                setters: {
                   
                },
                get_query() {
                    return {
                        filters: {  status: 'Closed' }
                    }
                },
                action(selections) {
                    if (selections && selections.length > 0) {
                        $.each(selections, function (i,items) {
                            frm.add_child("items", {
                                item_code:items 	
                            });
                            customer : items;
                            console.log(items);
                        });
                        frm.refresh_field("items");
                        $(".modal").modal("hide");
                    }
                }
            });
        }, __("Get Items From"));
    }
});

To the multi dialog box it ix working perfectly

if (selections && selections.length > 0) {
                        $.each(selections, function (i,items) {
                            frm.add_child("items", {
                                item_code:items 	
                            });
                            customer : items;
                            console.log(items);
                        });
   console.log(items); = >**here the document id is showing in the console**

can any oneplese help me to transfer the datas from one field to another