Remove multiple records from a collection- MongoDB - node.js

Question

I have two models with the following schemas:
Map:
var MapSchema = mongoose.Schema({
ownerId:{
type: Schema.Types.ObjectId,
ref: 'User',
required: true
},
mapName: {
type: String
},
mapImagePath:{
type: String,
required: true
},
createdAt: { type: Date, default: Date.now },
devices: [{type: Schema.Types.ObjectId, ref: 'Device'}]
});
Device:
var DeviceSchema = mongoose.Schema({
deviceName:{
type: String,
required: true,
index: true,
unique: true
},
roomCapacity: {
type: Number
},
roomImagePath:{
type: String,
},
mapId:{
type: Schema.Types.ObjectId,
ref: 'Map',
required: true
},
coords:{
type: [Number], //[xcoord, ycoord]
required: true
},
status:{
type: String,
required: true,
default: 'Available'
},
user:{
type: String,
},
createdAt: { type: Date, default: Date.now }
});
As you can see, one map has many devices. Now, When I delete a map, I want to delete all of the devices that belong to it. This should be easy because each map has an array of it's device ID's. But I can not seem to find a way to delete multiple records from a collection at once. I delete my map with this function:
module.exports.deleteMap = function(mapId, callback){
Map.findOneAndRemove({_id: mapId}, callback)
};
This returns the map so I can access it's device ID's as map.devices. However, how can I now use map.devices to remove all of these from the device collection? I was thinking something like device.remove(map.devices) ?

Answer 1

You can first find the map object and use the array of device _ids with the $in operator to remove all the devices in the map. Below is some (untested) sample code.
module.exports.deleteMap = function(mapId, callback) {
Map.findOneAndRemove({_id: mapId}, function(dbErr, map) {
if(dbErr) {
return callback(dbErr);
}
Device.remove({_id: {$in: map.devices}}, function(dbErr) {
if(dbErr) {
return callback(dbErr);
}
return callback(undefined, map);
});
});
};