将项目添加到Typescript中的数组

Question

I am working in TypeScript with MongoDB and I am trying to add an item to an array.

registeredUsers.update({ guid: ObjectId(req.cookies._id) }, {
    $addToSet: {
        favorites: [comicID]
    }
});

This is the code I have currently, and I am trying to add the comicID to an array called favorites that is in registeredUsers . At the moment it does not seem to be adding to the array at all, so when I try to look at the array it is empty.

Answer 1

Your code seems fine. I suspect the reason you are not getting updates is because your search condition is not matching any documents.

Have you tried the following statement:

 db.registeredUsers.find({ guid: ObjectId(req.cookies._id) })

If your search condition is valid, you should get the "desired" document back.

Here are my examples:

First create a doc.

> db.registeredUsers.insert({ "mycustom_id":1, "favorites":[1,2,3]})
WriteResult({ "nInserted" : 1 })

Check to see if the doc looks right.

> db.registeredUsers.find()
{ "_id" : ObjectId("56f88aa1d14e4832a027f625"), "mycustom_id" : 1, "favorites" : [ 1, 2, 3 ] }

Do an update based on one of the columns that I defined.

> db.registeredUsers.update({"mycustom_id" : 1}, { $addToSet: { favorites: 5}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

Check the update results:

> db.registeredUsers.find()
{ "_id" : ObjectId("56f88aa1d14e4832a027f625"), "mycustom_id" : 1, "favorites" : [ 1, 2, 3, 5 ] }

Now, do an update based on the "_id" field.

> db.registeredUsers.update({"_id":  ObjectId("56f88aa1d14e4832a027f625") }, { $addToSet: { favorites: 6}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

Checking the result:

> db.registeredUsers.find()
{ "_id" : ObjectId("56f88aa1d14e4832a027f625"), "mycustom_id" : 1, "favorites" : [ 1, 2, 3, 5, 6 ] }

Another example where the update is expected to create the array:

> db.registeredUsers.insert({"a":  1})
WriteResult({ "nInserted" : 1 })
> db.registeredUsers.find()
{ "_id" : ObjectId("56f88aa1d14e4832a027f625"), "mycustom_id" : 1, "favorites" : [ 1, 2, 3, 5, 6 ] }
{ "_id" : ObjectId("56f88be6d14e4832a027f626"), "a" : 1 }

Updating based on "_id" again in a situation where the array favorites does not exist prior to the update

> db.registeredUsers.update({"_id" : ObjectId("56f88be6d14e4832a027f626")}, { $addToSet: { favorites: 6}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

Check the results:

> db.registeredUsers.find()
{ "_id" : ObjectId("56f88aa1d14e4832a027f625"), "mycustom_id" : 1, "favorites" : [ 1, 2, 3, 5, 6 ] }
{ "_id" : ObjectId("56f88be6d14e4832a027f626"), "a" : 1, "favorites" : [ 6 ] }

As you can see my queries are identical to yours. You are comparing "guid" and I am comparing "_id". I am suspicious that "guid" does not contain what you expect it to contain, which leads to your "search condition" to the update to return 0 documents, consequently