"pre" and "post" remove Middleware not firing - node.js

Question

I have implemented two different ways to remove a user and not one of them fires the "pre" and "post" remove Middleware.
As I understand
Below are my two different implementations in my model file:
Method One:
var User = module.exports = mongoose.model('User', userSchema);
userSchema.pre('remove', function(next) {
// 'this' is the client being removed. Provide callbacks here if you want
// to be notified of the calls' result.
//Vouchers.remove({user_id: this._id}).exec();
console.log("pre test");
next();
});
userSchema.post('remove', function(next) {
// 'this' is the client being removed. Provide callbacks here if you want
// to be notified of the calls' result.
//Vouchers.remove({user_id: this._id}).exec();
console.log("post test");
next();
});
// Remove User
module.exports.removeUser = function(id, callback){
var query = {_id: id};
console.log('test');
//User.remove(query, callback);
User.find(query).remove(callback);
}
Method Two:
var User = module.exports = mongoose.model('User', userSchema);
userSchema.pre('remove', function(next) {
// 'this' is the client being removed. Provide callbacks here if you want
// to be notified of the calls' result.
//Vouchers.remove({user_id: this._id}).exec();
console.log("pre test");
next();
});
userSchema.post('remove', function(next) {
// 'this' is the client being removed. Provide callbacks here if you want
// to be notified of the calls' result.
//Vouchers.remove({user_id: this._id}).exec();
console.log("post test");
next();
});
// Remove User
module.exports.removeUser = function(id, callback){
var query = {_id: id};
console.log('test');
User.remove(query, callback);
}

Answer 1

This is how I got everything working:
// Remove User
module.exports.removeUser = function(id, callback){
User.findById(id, function (err, doc) {
if (err) {
}
doc.remove(callback);
})
}
//Remove vouchers related to users
userSchema.pre('remove', function(next) {
this.model('Voucher').remove({ user: this._id }, next);
});

Answer 2

http://mongoosejs.com/docs/middleware.html
Please refer to the documentation. By design the middleware hook for remove is not fired for Model.remove, only for ModelDocument.remove function.

Answer 3

Anyone else searching for the same. deleteOne and deleteMany middlewares can be used with pre and post middlewares. Remove has been deprecated from the latest mongo release.
The code below got things working for me.
ModelSchema.pre("deleteOne", { document: true }, function(next) {
let id = this.getQuery()["_id"];
mongoose.model("Model_two").deleteMany({ property: id }, function(err, result) {
if (err) {
next(err);
} else {
next();
}
});
});

Answer 4

For anyone having the issue in future, check that you defined your hooks before calling mongoose.model().
Define Middleware Before Compiling Models
Calling pre() or post() after compiling a model does not work in Mongoose in general. For example, the below pre('save') middleware will not fire.
...
https://mongoosejs.com/docs/middleware.html#defining

Answer 5

You need to add
{document:false,query:true}
parameter to userSchema('remove',callback) middleware for Query.remove(). It is also important to understand difference between query middleware and document middleware.
Query middleware and Query.remove()
UserSchema.pre('remove',callback) will not be fired by default if it is a query middleware. As a solution
var User = module.exports = mongoose.model('User', userSchema);
//...
userSchema.pre('remove',{document:false,query:true}, callback);
//...
module.exports.removeUser = function(id, callback){
User.remove(callback);
}
We pass {document:false,query:true} parameter to middleware.
User.remove(callback)//Query.remove()
will not return a document from database.It will execute a remove operation and it will not call doc.remove(). It will call Query.remove().
Document middleware and doc.remove()
userSchema.pre('remove',callback) is registered as a document middleware by default.
The code snippet below will run smoothly without additional parameters.
var User = module.exports = mongoose.model('User', userSchema);
//...
userSchema.pre('remove', callback);
//...
module.exports.removeUser = function(id, callback){
User.find(query).remove(callback);//doc.remove()
}
userSchema.pre('remove',callback) will be fired because User.find(query) returns a mongoose document from database and User.find(query).remove(callback) will call doc.remove()

Answer 6

Only document middleware
// query document and delete
schema.findOne({ _id: id}).then((doc) => {
doc.remove().then(() => {
console.log(`it works!`)
})
})
// schema
schema.pre('remove', { document: true, query: false }, function() {
console.log('Removing doc!')
})
The delete was deprecated, try to use deleteOne instead.
Only query middleware. This will get called when you do Model.deleteOne() but not doc.remove().
// delete from model
schema.deleteOne({ _id: id }).then((removed) => {
console.log(`it works!`)
}
// schema
schema.pre('deleteOne', { query: true, document: false }, function() {
let id = this.getQuery()['_id']
console.log(`${id} was Removing!`)
})

Answer 7

Make sure you're using the exact functions that you're calling, eg pre('save') and pre('updateOne') do not get called for model.findOneAndUpdate()