使用Mongoose更新MongoDB文档而不删除文档中已有的信息

Question

So what I want to do is add on to an object in the document not delete the whole thing. I have a document with an array in it and if I call findOneAndUpdate it adds what I want but gets rid of everything already in the array.

All I want to do is keep what I already have in my array and add one more item.

Here is my code:

Friends.findOneAndUpdate({facebookId: value.id}, {$set: {friends: {id: profile.id, name: profile._json.name}} }, {new: false}, function (err, friends) {
    if(err){
      console.log("Something went wrong when updating data!");
    }

    console.log("success saving user friend update");
});

And here is what happens with my array in the database:

This:

"friends": [
    {
        "id": "114222474148205",
        "name": "Chris Chang"
    },
    {
        "id": "903622474147290",
        "name": "Johny Unitas"
    },
    {
        "id": "685034985392094",
        "name": "Mary Jane"
    }
]

To this:

"friends": {
    "id": "49572957395733524",
    "name": "John Doe"
}

What I want is those two to be combined.

So how would I "add" an item and not "update" the item?

Answer 1

As Joao said above; all I you have to do is change $set to $push.

So this:

Friends.findOneAndUpdate({facebookId: value.id}, {$push: {friends: {id: profile.id, name: profile._json.name}} }, {new: false}, function (err, friends) {

instead of this:

Friends.findOneAndUpdate({facebookId: value.id}, {$set: {friends: {id: profile.id, name: profile._json.name}} }, {new: false}, function (err, friends) {