Nested Mongoose queries data not showing on GraphQL query - node.js

Question

I'm trying to create an API using Apollo-server with GraphQL and Mongoose.
My problem is that the query to Mongoose does return the data, but the GraphQL model shows as null when I test.
I've tried different methods and using promises.
type Articulo {
id: ID
nombre: String
codigoDeBarras: String
codigo: String
}
type EntradaInventario {
id: ID
articulo: Articulo
inventario: Inventario
cantidad: Float
}
type Almacen {
id: ID
nombre: String
}
type Inventario {
id: ID
almacen: Almacen
nombre: String
}
type Query {
articulo(codigoDeBarras: String): Articulo
entradaInventario(inventario: String): [EntradaInventario]
}
type Mutation {
addEntradaInventario(idArticulo: String, idInventario: String, cantidad: Float): EntradaInventario
addAlmacen(nombre: String): Almacen
addInventario(idAlmacen: String, nombre: String): Inventario
}
const EntradaInventarioModel = Mongoose.model("EntradaInventario", {
_id: Schema.Types.ObjectId,
idArticulo: {type: Mongoose.Schema.Types.ObjectId, ref: 'Articulo'},
idInventario: {type: Mongoose.Schema.Types.ObjectId, ref: 'Inventario'},
cantidad: Number
}, "entradainventarios");
Query: {
articulo: (_, args) => ArticuloModel.findOne({
'codigoDeBarras': args.codigoDeBarras
}).exec(),
entradaInventario: (_, args) =>
EntradaInventarioModel.find({idInventario: args.inventario})
.populate('idArticulo')
.exec(),
}

Answer 1

You shouldn't use the populate on the Parent model. You should instead define how to query the nested model in the EntradaInventario resolvers.
Inventory should look something like this:
Inventory : {
articulo: async (parent, args, { }) => {
return await Articulo.findOne({
_id: parent.idArticulo,
});
},
}
Here is a repo that does just that and is a good example https://github.com/the-road-to-graphql/fullstack-apollo-express-mongodb-boilerplate