How to populate nested object ref

[yogesh bansal]

Hi,

I have nested object ref and i want to populate it. My schema is something like this

var product = new Schema({
    product: {type:Schema.Types.ObjectId, ref:'product'},
    count: Number
});

var orderSchema = new Schema({
    orderItems :[product],
});

var customerSchema = new Schema({
    orders: [{type: Schema.Types.ObjectId, ref: 'orders'}],
});

I want to all the orders of a customer and all the items in each order.

Please guide me how can i populate it

Thanks