How to create array of object ids in ref mongoose?

I am trying to create an order in the post method. I have two documents - Order, OrderItem. Schemas are-

var OrderSchema = new Schema({
     name: String,
     orderItems : [{ type: Schema.Types.ObjectId, ref: 'orderitems' }]
 });

 var orderItemsSchema = new Schema({
     name: String,
     products : String
 }); 

My controller function --

let itemArr: any[] = [];
  req.body.orderItems.map(async (item: { products: any; quantity: any }) => {
    const newOrdeItem = new OrderItems({
      products: item.products,
      quantity: item.quantity,
    });
    const items = await newOrdeItem.save();
   //found ids
    itemArr.push(items._id);
    
  });
   //not found ids
  itemArr.push(items._id);

  const newOrder = new Order({
    orderItems: itemArr,
    phone: req.body.phone,
  });
  const order = await newOrder.save();
  return res.json(order);

I want to make an order. req.body data are--

{
    "orderItems" : [
        {
            "quantity": 3,
            "product" : "Orange"
        },
        {
            "quantity": 2,
            "product" : "Banana"
        }
    ],
    "phone": "+420702241333",
}

How can I solve this issue?

I understand you need to get the orderItems from the ref ? if that can you use populate

order.populate('orderItems')

//Edit

frist require your model from monngoose after that make insertMany or save fn like

   const dbOrders = require('pathOfModel')
   orderResult = await dbOrders.insertMany({
     name : req.body.name || 'Name you need insert in Schema',
     orderItems : itemArr 
   })
  console.log(orderResult) // res.json(orderResult)