MongoDB $push is not actually pushing anything onto the array - node.js

Question

I commented the line of code with // This Command Does not work where I suspect that it is breaking. In the debug log of mongoose, the output looks like this: But nothing is added to the medicineIds array in the Monday object for the DaysOfWeek schema.
The following is the debug output for DayOfWeek.findOneAndUpdate() where I push back onto the array, and am not seeing the result in my mongo database.
Mongoose: dayofweeks.insertOne({ medicineIds: [], _id: 'Monday', __v: 0 }, { session: null }) // <- response to $push
Mongoose: medicines.insertOne({ times: [ 1, 2 ], dayNames: [ 'Monday' ], _id: ObjectId("5e73d816d54b1202e15bb96b"), nam
e: 'Provolone', count: 23, __v: 0 }, { session: null })
Mongoose: dayofweeks.findOne({ _id: 'Monday' }, { projection: {} })
Mutation
const Mutation = new GraphQLObjectType({
name: 'Mutation',
fields: {
addDayOfWeek: {
type: DayOfWeekType,
args: {
name: { type: new GraphQLNonNull(GraphQLString) }
},
resolve(parent, args) {
let dayOfWeek = new DayOfWeek({
_id: args.name,
medicineIds: new Array()
});
return dayOfWeek.save();
}
},
addNewMedicine: {
type: MedicineType,
args: {
name: { type: new GraphQLNonNull(GraphQLString) },
count: { type: new GraphQLNonNull(GraphQLInt) },
times: { type: new GraphQLNonNull(GraphQLList(GraphQLInt))},
dayNames: { type: new GraphQLNonNull(GraphQLList(GraphQLString))}
},
resolve (parent, args) {
let medicine = new Medicine({
name: args.name,
count: args.count,
times: args.times,
dayNames: args.dayNames
});
args.dayNames.forEach((dayId) => {
DayOfWeek.findOneAndUpdate( // This Command Does Not Work:
// medicine._id, dayId are correct at this point of the
//code
{ _id: dayId },
{ $push: { medicineIds: medicine._id }},
{ new: true, useFindAndModify: false }
);
});
return medicine.save();
}
}
}
});
DayOfWeek Schema
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const dayOfWeekSchema = new Schema({
_id: String,
medicineIds: [String] // I am trying to push onto this array
});
module.exports = mongoose.model('DayOfWeek', dayOfWeekSchema);
Medicine Schema
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const medicineSchema = new Schema({
id: String,
count: Number,
name: String,
times: [Number],
dayNames: [String]
});
module.exports = mongoose.model('Medicine', medicineSchema);

Answer 1

await Promise.all(args.dayNames.map(dayName => {
return DayOfWeek.findOneAndUpdate({ _id: dayName }, { $push: { medicineIds: medicine._id }});
})).catch((err) => console.error(err));
return await medicine.save();
I just did that and it works. hmm.