Issue in saving values in array in mongoose model using save() [duplicate] - node.js

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This question already has answers here:
Push items into mongo array via mongoose
(11 answers)
Closed 5 years ago.
I am trying to update a document in a collection. I am particularly trying to update an array of Strings.The following is my Schema
var sampleSchema= mongoose.Schema({
fullName : String,
email : String,
rolesTaken : [String],
});
I basically have an array of such schema's. I want to update the rolesTaken array for all of them.
So I did the following
var async = require('async');
var ATmapping = require('path to Schema');
ATmapping.find({},function(err,lists){
if(err){
console.log(err);
return;
}
if(lists.length > 0){
async.each(lists,function(list,callback){
if(!list.rolesTaken){
list.rolesTaken =[];
}
list.rolesTaken.push("Patient");
list.markModified('rolesTaken');
list.save(function(err,item){
if (err){
console.log(err);
}
console.log('Saved', item);
callback();
});
});
}
});
I have browsed a lot and the most popular solution was to add markModified. But it doesn't seem to work in my case.When I added mongoose.debug i got the following
atmappings.update({ _id: ObjectId("59074b127adeef0004b84ac3"), __v: 7 }, { '$set': { rolesTaken: [] }, '$inc': { __v: 1 } })
As you can see the roles taken is empty despite me adding markmodified and save(). I would like to know if I am missing something which is preventing me from saving the values in the schema.
Thanks in advance.

Answer 1

Here is how I push a comment to a thread in one of my apps using mongoose.
Thread.findByIdAndUpdate(body.thread, { $push: { comments: comment.id }})
I simply find the thread by the id, then use the $push operator to push the comment id to the comments attribute where I populate later.
You can read more into the $push operator here (mongoose v3.4) https://docs.mongodb.com/manual/reference/operator/update/push/