Mongoose nested schemas - node.js

Question

I'm creating an app where you log workouts and I'm having some problems with Mongoose.
I have two schemas, one for workouts and one for exercises. When the user adds a new exercise, I want it to be stored inside the workout, and I've been trying this in a bunch of ways.
For now, the exercises are saved in a different collection in my MongoDB (don't know if this is the best way to do it), and I thought that it should save the exercise inside the workout.exercises, but there is only the objectID. How do I resolve this? Have looked at the populate function, but can't figure out how to get it to work.
addExercises
export function addExercise(req, res) {
if (!req.body.exercise.title) {
res.status(403).end();
}
const newExercise = new Exercise(req.body.exercise);
// Let's sanitize inputs
newExercise.title = sanitizeHtml(newExercise.title);
newExercise.cuid = cuid();
newExercise.sets = [];
newExercise.save((err, saved) => {
if (err) res.status(500).send(err);
});
Workout
.findOneAndUpdate(
{cuid: req.body.exercise.workoutCUID},
{$push: {exercises: newExercise}},
{upsert: true, new: true},
function (err, data) {
if (err) console.log(err);
});
}
getExercises
export function getExercises(req, res) {
Workout.findOne({cuid: req.params.cuid}).exec((err, workout) => {
if (err) {
res.status(500).send(err);
}
console.log(workout);
let exercises = workout.exercises;
res.json({exercises});
});
}
Workout
import mongoose from "mongoose";
const Schema = mongoose.Schema;
var Exercise = require('./exercise');
const workoutSchema = new Schema({
title: {type: 'String', required: true},
cuid: {type: 'String', required: true},
slug: {type: 'String', required: true},
userID: {type: 'String', required: true},
exercises: [{ type: Schema.Types.ObjectId, ref: 'Exercise' }],
date: {type: 'Date', default: Date.now, required: true},
});
export default mongoose.model('Workout', workoutSchema);
Exercise
import mongoose from "mongoose";
const Schema = mongoose.Schema;
var Workout = require('./workout');
const exerciseSchema = new Schema({
title: {type: 'String', required: true},
cuid: {type: 'String', required: true},
workoutCUID: {type: 'String', required: true},
sets: {type: 'Array', "default": [], required: true}
});
export default mongoose.model('Exercise', exerciseSchema);

Answer 1

Based on your Workout schema, you declare the type of the Exercises field to be [{ type: Schema.Types.ObjectId, ref: 'Exercise' }]. This means that this field should be an array of Mongoose ObjectId's.
It appears that you are attempting to add the whole exercise object to the workout's exercises field, rather than just the ObjectId. Try modifying it this way:
const newExercise = new Exercise(req.body.exercise);
// Let's sanitize inputs
newExercise.title = sanitizeHtml(newExercise.title);
newExercise.cuid = cuid();
newExercise.sets = [];
newExercise.save((err, saved) => {
if (err) res.status(500).send(err);
// Nest the Workout update in here to ensure that the new exercise saved correctly before proceeding
Workout
.findOneAndUpdate(
{cuid: req.body.exercise.workoutCUID},
// push just the _id, not the whole object
{$push: {exercises: newExercise._id}},
{upsert: true, new: true},
function (err, data) {
if (err) console.log(err);
});
});
Now that you correctly have the ObjectId saved in the exercises field, .populate should work when you query the workout:
Workout.findById(id).populate("exercises").exec((err, workout) => {
// handle error and do stuff with the workout
})

Answer 2

Workout.findById(req.params.id).populate("exercises").exec((err,workout) =>{
res.status(200).json(workout);
})
It should work this way