mongoose update array or add to the array

Question

I\'ve been trying to get this running for a while now but I can\'t figure out what I\'m doing wrong.

I have two schemas like this

const paymentSchema = n         


        

Answer 1

Consider the two input documents. The first one will be inserted (the year_month: '2020_03' doesn't exist in the payments array). When the update is run with the second one it will update the statusof the existing sub-document in the array.

The update operation is valid with the MongoDB version 4.2 or later only, as it uses a pipeline for the update.

INPUT_DOC = { year_month: '2020_03', status: false }    // this will get inserted into the array
INPUT_DOC = { year_month: '2020_02', status: true }     // updates the sub-document

db.collection.findOneAndUpdate(
  { 
      _id: "5e90ae0e0ed9974174e92826" 
  },
  [ 
      { 
          $set: { 
              payments: {
                  $reduce: {
                      input: "$payments", 
                      initialValue: { payments: [], update: false },
                      in: {
                          $cond: [ { $eq: [ "$$this.year_month", INPUT_DOC.year_month ] },
                                   { 
                                      payments: { 
                                          $concatArrays: [
                                               [ { _id: "$$this._id", year_month: "$$this.year_month", status: INPUT_DOC.status } ],
                                               "$$value.payments"
                                           ] 
                                      }, 
                                      update: true
                                   },
                                   { 
                                      payments: { 
                                          $concatArrays: [  [ "$$this" ], "$$value.payments" ] 
                                      }, 
                                      update: "$$value.update" 
                                   }
                          ]
                      }
                  }
              }
          }
      },
      { 
          $set: { 
              payments: { 
                  $cond: [ { $eq: [ "$payments.update", false ] },
                           { $concatArrays: [ [ INPUT_DOC ], "$payments.payments" ] },
                           { $concatArrays: [ [ ], "$payments.payments" ] }
                  ] 
              }
          }
      }
  ],
  { 
      new: true, 
      upsert: true 
  }
)