feathers-mongodb Service.find({query: {_id}}) returns null - mongodb

Question

I have the schemas below:
students.graphql.schema.js
export default [
`
type StudentsWithPagination {
total: Int
items: [Students]
}
type Students {
_id: String!
name: String
address: Addresses
}
`,
];
addresses.graphql.schema.js
export default [
`
type AddressesWithPagination {
total: Int
items: [Addresses]
}
type Addresses {
_id: String!
title: String
}
`,
];
I have created two services by running feathers generate service students.service.js and addresses.services.js.
When I search addresses by title, I get result. However, when I search by _id, I get null. Something like:
const studentsResolvers = {
Students: {
address: student => {
const query = {
_id: student.address
}
return Addresses.find({ query }).then(result => {
console.log(result)
})
}
}
}
The code above produces null though student.address returns the right address._id. I still get null even I hardcode student.address with the right address._id
The code above will return null unless I search by address title. Something like:
const query = {
title: 'my-location'
}
_id is of type String, not ObjectID.
What am I doing wrong?

Answer 1

As documented in the feathers-mongodb adapter, since MongoDB itself (unlike Mongoose) does not have a schema, all query parameters have to be converted to the type in the database in a hook manually. The example can be adapted accordingly for $in queries:
const ObjectID = require('mongodb').ObjectID;
app.service('users').hooks({
before: {
find(context) {
const { query = {} } = context.params;
if(query._id) {
query._id = new ObjectID(query._id);
}
if(query.age !== undefined) {
query.age = parseInt(query.age, 10);
}
context.params.query = query;
return Promise.resolve(context);
}
}
});