mongoose model multiple key types - node.js

Question

I have a simple schema as
const xpReward = new mongoose.Schema({
...,
receivedFor: {
type: Object,
required: true
}
});
Received for is an object which can have 2 keys and the values can be something like { "articleId": 5} or { "testId": 7}
I want to expand this receivedFor object with an required field, but keeping the possibility to add articleId or testId.
I know I can let it as in example above, because is an object and can have any form, but I want to specify the type there, to can be known in further usage.
I'm thinking at something like:
const xpReward = new mongoose.Schema({
...,
receivedFor: {
learningPath: {
type: String,
required: true
},
articleId | testId: {
type: Number,
required: true
}
}
});
I don't want to use another nested object as
receivedFor: {
learningPath: {
type: String,
required: true
},
// in this example, the old receivedFor will become this valueFor
// this will be just another nested level, one more parent for it
valueFor: {
type: Object,
required: true
}
}
Can be this done somehow better? thx

Answer 1

Would likely need some hooks to go along with this, but this is the basic idea.
const xpReward = new mongoose.Schema({
...,
receivedFor: {
learningPath: {
type: String,
required: true
},
foreignId: {
type: Number,
required: true
},
foreignCollection: { // maybe even make it an enum - articleId | testId
type: String,
required: true
}
}
});