mongoose get id code example

Example 1: where id and id in mongodb

const p_id = patient_id;
    let fetchingReports = await Reports.aggregate([
      ...(p_id
        ? [
            {
              $match: {
                createdBy: mongoose.Types.ObjectId(id),
                patient_id: p_id,
              },
            },
          ]
        : [
            {
              $match: {
                createdBy: mongoose.Types.ObjectId(id),
              },
            },

Example 2: mongoose save return id

//if you are sending an id field in req.body then mongoose will return e null _id
//to solve this just delete the _id field before running the save method
if(req.body._id === null) {
  delete req.body._id;
}