猫鼬如何有条件推入嵌套数组

Question

Suppose I have the following schema:

{
  userId: docId,
  skills: [
    {
      _id: SkillId,
      endorsers: [
        {
          userId: idOfUser
        }
      ]
    }
  ]
}

What I want is a user should not be able to endorse a specific skill in a document more than once. First should find a specific document using its docId , and inside that, a specific skill using skillId , and then check if its endorsers array is empty or a specific user not endorsed yet, then push. What I tried so far:

    {
      "userId": req.params.userId,
      "skills": {
        "$elemMatch": {
          "skillId": ObjectId(req.params.skillId),
          "$or": [
            {"endorsers": []},
            {"endorsers.userId":{$ne: endorser._id}}
          ]
        }
      }
    },
    {
      "$push": { "skills.$[outer].endorsers": endorserData }
    },
    {
      "arrayFilters": [
        { "outer.skillId": ObjectId(req.params.skillId) }
      ]
    }

But this is not working, and along update, I need the updated result.

Answer 1

You can use addToSet function of mongoose arrays to keep their elements unique. https://mongoosejs.com/docs/api.html#mongoosearray_MongooseArray-addToSet