MongoDB Atlas 触发器未设置字段

Question

I have the following trigger function that is not function. I would like to know why it does not set the field createdAt:

const collection = context.services.get("comand-dev").db("test").collection("ownerDetails");
  const docId = changeEvent.documentKey._id;
  collection;
  collection.updateOne(
    {_id : docId} ,
    { 
      $set : 
        {
        createdAt: Date()
        } 
    }
  );

The trigger logs says OK but the field is not there

Answer 1

This worked for me. A small issue with the syntax. you have to add the quotes.

collection.updateOne(
{"_id" : docId} ,
    { 
      "$set" : 
        {
        "createdat": Date()
        } 
    }
);

Answer 2

I was able to figure out so I would share my solution. In my case, I convert _id object id to date and insert it as a new field for newly inserted document. The trigger will be configurated as insert trigger operation. Enable event ordering.

 exports = function (changeEvent) {
 const docId = changeEvent.documentKey._id;
 console.log(docId);
 const collection = 
 context.services.get("Cluster0").db("Driver").collection("Trip");
 collection.updateOne({_id: docId },
 [{
    "$addFields" : {
        "CreationDate" : {
            "$toDate" : "$_id"
        }
    }
}],{upsert: false}
);
};