MongoDB-mongoose, Array filter-CodePudding

I have an issue with array object.

    "userId": "63317e7f9746ba9719845b6e",
    "items": [
        {
            "productId": "Z357",
            "piece": 1,
            "_id": "63333427d7ea226b2462e734"
        },
        {
            "productId": "A541",
            "piece": 1,
            "_id": "6333342cd7ea226b2462e738"
        },
        {
            "productId": "G31",
            "piece": 1,
            "_id": "633334ea1ca2b582ddd0bc62"
        },
        {
            "productId": "K1123",
            "piece": 1,
            "_id": "6333351028b43b58b8f83ba3"
        }
    ],

I have an array like that. I want to get specific item with productId,

const checker = await Cart.findOne({
      "items.productId": productId,
    });

I'm checking an array like that, but it's giving me all of the items that contain productId, how can I get only what am I filter?

CodePudding user response：

try using find instead of findOne and see if it works

CodePudding user response：

You can try this way with projection to get only the matched element where your productId is equal to the provided productId,

const checker = await Cart.findOne({items:{ $elemMatch:{ productId: productId}}},
  {userId:1,"items.$": 1});