mongoose populate doesn't work with array of IDs

Question

I have these two 3 models User, Product and Orders and are also has references to each other.

My Orders Schema:

const orderSchema = Schema({

buyerId:{
    type: Schema.Types.ObjectId,
    ref: 'User'
},
totalAmount: {
    type: Number,
    required: [true, "description is required"]
},
    createdOn: {
    type: Date,
    default: new Date()
},
    items:[{type:Schema.Types.ObjectId, ref: 'Product'}]})

I'm trying to use populate() like this:

    Order.find()
    .populate('buyerId')//Reference to User Model
    .populate('items')// Reference to Product Model
    .exec(function (err, result){

        console.log(result);// RETURNS ONLY buyerId populated
        console.log(result.buyerId.name);//Successfully references to my User model and prints name
        console.log(result.items);//Prints Undefined

    })

You can see my console log above and what it returns is only the populated buyerId(only got the reference from my User model)

Seems like my populate('items') doesnt work at all. The items field contains array of IDs, where the IDs are those of products. I need to reference to User and Product both. I'm just following the documentation in mongoose, I don't know what I might be doing wrong.

If you don't put .populate('items'), does items contain a list of ids or still undefined ? Because, then there might be something wrong with the way you add a new product inside your order, or with the models. — jeremynac
– jeremynac, Commented Sep 12, 2021 at 13:50
@jeremynac if I remove it and just leave the populate buyer Id I can reference and get the data from the User collection — quielfala
– quielfala, Commented Sep 12, 2021 at 13:56
Ok, if you just put .populate('items'), are items populated ? — jeremynac
– jeremynac, Commented Sep 12, 2021 at 14:01

mohammad Naimi · Accepted Answer · 2021-09-12 15:46:45Z

1

use aggregate

Order.aggregate([
    { $match:{ user:"sample_id"
     }
    },
    {$lookup:{
        from:'users', // users collection name
        localField:'buyerId',
        foreignField:'_id',
        as:'buyerId'
    }},
    {
        $lookup:{
            from:'items', //items collection name
            localField:'items',
            foreignField:'_id',
            as:'items'
        }
    },

])

edited Sep 12, 2021 at 15:46

answered Sep 12, 2021 at 13:37

mohammad Naimi

2,3591 gold badge7 silver badges19 bronze badges

Sign up to request clarification or add additional context in comments.

13 Comments

quielfala Over a year ago

How do I reference to those as: fields and as: buyerId? How do I output the result? I connected .then(result) at the end of your code and console log it but just got the documents from Order collections

mohammad Naimi Over a year ago

lookup as field put populated data as field name we defined in lookup as value of as, from is collection name of each schema you want populate , I don't know the collection names , so I just make query to change it as your environment

quielfala Over a year ago

Oh I think I'm getting it now. Thank you, I'll update here.

quielfala Over a year ago

Thank you problem solved. I've been dealing with this for hours.

mohammad Naimi Over a year ago

you could add another stage match now I will update my answer

|

Collectives™ on Stack Overflow

mongoose populate doesn't work with array of IDs

1 Answer 1

13 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

13 Comments

Your Answer

Sign up or log in

Post as a guest

Related