mongoose, how to correctly remove reference with middleware? - node.js

Question

can someone help me with a mongoose operation? I'm currently building this voting system.
I have this Poll model as:
var Poll = new Schema({
title: {
type: String,
required: true
},
options: [{text:String, count: {type: Number, default: 0}}],
author: {
type: Schema.ObjectId,
ref: 'Account',
},
disabled: {
type:Boolean,
default: false,
},
date: {type: Date, defalut: Date.now},
});
and I have this Log model as:
var Log = new Schema({
ip: String,
voter: {
type: Schema.ObjectId,
ref: 'Account'
},
poll: {
type: Schema.ObjectId,
ref: 'Poll'
},
date: {type: Date, defalut: Date.now},
});
each time a user vote for something , log will create something like:
{ ip: '::1',
voter: 5824e7c3b6e659459818004f,
poll: 58264b48f767f2270452b5cb,
_id: 58264b4cf767f2270452b5ce }
now should a user delete one of his poll, say 58264b48f767f2270452b5cb , I would like to also remove all the log documents that has same poll id in it.
I read some other answer and came up a middleware with
Poll.pre('remove', function(next){
var err = new Error('something went wrong');
this.model('Log').remove({poll: this._id}, function(err){
if (err) throw err;
})
next(err);
});
but it's not working at all.
what should I do? Thanks.

Answer 1

At the current state Model.remove() calls don't use hooks, why? Because a document could not be present in memory at time of the call, so would be necessary to query mongo first and then delete the doc to make sure a hook would work properly.
There's a CR for adding this behavior but is not implemented, yet.
So the current way to do this is to use something like:
myDoc.remove();
An example, this won't work:
var myAccount = new Account({
name: "jim"
})
var myPoll = new Poll({
question: "You like stuff?"
})
var myLog = new Log({
voter: myAccount,
poll: myPoll
})
myAccount.save()
.then(myPoll.save())
.then(myLog.save())
.then(Poll.remove({
question: "You like stuff?"
}, function(err) {
console.log(err)
}))
This will work instead:
myAccount.save()
.then(myPoll.save())
.then(myLog.save())
.then(myPoll.remove(function(err) {
console.log(err)
}))