How to remove objects from an array within a mongoose model - node.js

Question

I am trying to remove multiple objects that are in an array in mongoose. My Workout model look like this:
{
_id: 5e04068491a2d433007026cd,
exercises: [
{ _id: 5e0401b9dda7ea28a70e99ed, reps: '1', sets: '3' },
{ _id: 5e0401cadda7ea28a70e99ee, reps: '1', sets: '3' },
{ _id: 5e0401dbdda7ea28a70e99ef, reps: '1', sets: '3' }
]
}
I have an array of id's, named deletedExercises, these are the ids of the objects that I want removed from the exercise list. I am trying to loop through deletedExercise and remove any exercises that match the id of the deletedExercise item.
router.put("/:workoutId", (req, res)=>{
deletedOnes = req.body.exerciseId
deletedExercises = []
if(typeof deletedOnes === 'object'){
deletedOnes.forEach(item => {
deletedExercises.push(item)
})
} else {
deletedExercises.push(deletedOnes)
}
deletedExercises.forEach(item => {
Workout.findByIdAndUpdate( req.params.workoutId,
{ $pull: { exercises: { _id: item} } } )
});

Answer 1

You can simply delete exercises using the $in operator inside $pull like this:
router.put("/:workoutId", (req, res) => {
console.log(req.body.exerciseId); //[ '5e05c5306e964f0a549469b8', '5e05c5306e964f0a549469b6' ]
Workout.findByIdAndUpdate(
req.params.workoutId,
{
$pull: {
exercises: {
_id: {$in: req.body.exerciseId}
}
}
},
{ new: true }
)
.then(doc => {
res.send(doc);
})
.catch(err => {
console.log(err);
res.status(500).send("Error");
});
});
Let's say we have this workout with 3 exercises:
{
"_id": "5e05c5306e964f0a549469b5",
"exercises": [
{
"_id": "5e05c5306e964f0a549469b8",
"reps": 8,
"sets": 4
},
{
"_id": "5e05c5306e964f0a549469b7",
"reps": 10,
"sets": 3
},
{
"_id": "5e05c5306e964f0a549469b6",
"reps": 12,
"sets": 2
}
],
}
If we want to remove the exercises 5e05c5306e964f0a549469b8 and 5e05c5306e964f0a549469b6 for this 5e05c5306e964f0a549469b5 workout, we can send a PUT request with this body: (url must end something like this http://.../5e05c5306e964f0a549469b5)
{
"exerciseId": [
"5e05c5306e964f0a549469b8",
"5e05c5306e964f0a549469b6"
]
}
The response will be:
{
"_id": "5e05c5306e964f0a549469b5",
"exercises": [
{
"_id": "5e05c5306e964f0a549469b7",
"reps": 10,
"sets": 3
}
]
}

Answer 2

Hard to tell considering you're not saying what error you are getting, but my guess from looking at it is that you are comparing an ObjectId with a String, try to replace this line:
{ $pull: { exercises: { _id: item} } } )
with this:
{ $pull: { exercises: { _id: new ObjectId(item)} } } )
** EDIT **
you probably need to also convert the main ID you are searching for to an ObjectId:
Workout.findByIdAndUpdate( new ObjectId(req.params.workoutId),
{ $pull: { exercises: { _id: new ObjectId(item)} } } )