Remove object from nested array of objects-CodePudding

I got this user schema

const UserSchema = new Schema({
  email: {
    type: String,
    required: true,
    unique: true,
  },
  groups: [
    {
      groupName: {
        type: String,
        required: true,
      },
      groupMembers: [{ type: Schema.Types.ObjectId, ref: "GroupMember" }],
    },
  ],
});

And I want to delete a group from the ‘groups’ array based on given ‘userId’ and ‘groupId’, my attempt (with express and mongoose):

router.delete(  
  "/:userId/:groupId",
  catchAsync(async (req, res) => {
    const { userId, groupId } = req.params;
    const updatedUser = await User.findByIdAndUpdate(
      userId,
      { $pull: { "groups.$._id": groupId } },
      { new: true }
    );
    res.send({ updatedUser });
  })
);

The response of the request: I get an error: “The positional operator did not find the match needed from the query.”

CodePudding user response：

Assuming an actual doc might look like this (using strings instead of ObjectId to keep the example tighter):

    {_id:1, groups: [ { type: "ID1", ref: "XX" }, { type: "ID2", ref: "G1" }, { type: \
"ID3", ref: "G2" } ] }

then this update will remove the subdoc in the groups array where _id = 1 and type = ID2:

db.foo.update({_id:1},  
              { $pull: { groups: { type: "ID2" } }}
             );